#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_NODES 100

typedef struct Node {
    void *data;
    struct Node *next;
} Node;

typedef struct {
    Node *head;
    Node *tail;
    int size;
} LinkedList;

typedef struct {
    LinkedList **neighbors;
    int nodes;
} ListGraph;

typedef struct {
    LinkedList *list;
} Queue;


void init_list(LinkedList *list);

void add_nth_node(LinkedList *list, int n, void *new_data);

Node* remove_nth_node(LinkedList *list, int n);

int get_size(LinkedList *list);

void free_list(LinkedList **list);

void print_int_linkedlist(LinkedList *list);

void print_string_linkedlist(LinkedList *list);

void init_list_graph(ListGraph *graph, int nodes);

void add_edge_list_graph(ListGraph *graph, int src, int *dest);

int has_edge_list_graph(ListGraph *graph, int src, int dest);

LinkedList* get_neighbours_list_graph(ListGraph *graph, int node);

void remove_edge_list_graph(ListGraph *graph, int src, int dest);

void clear_list_graph(ListGraph *graph);

void init_q(Queue *q);

int get_size_q(Queue *q);

int is_empty_q(Queue *q);

void* front(Queue *q);

void dequeue(Queue *q);

void enqueue(Queue *q, void *new_data);

void clear_q(Queue *q);

void purge_q(Queue *q);





void init_list(LinkedList *list) {
    list->head = NULL;
    list->tail = NULL;
    list->size = 0;
}

void add_nth_node(LinkedList *list, int n, void *new_data) {
    Node *prev, *curr;
    Node *new_node;

    if (list == NULL) {
        return;
    }

    /* n >= list->size inseamna adaugarea unui nou nod la finalul listei. */
    if (n > list->size) {
        n = list->size;
    } else if (n < 0) {
        return;
    }

    curr = list->head;
    prev = NULL;
    while (n > 0) {
        prev = curr;
        curr = curr->next;
        --n;
    }

    new_node = malloc(sizeof(Node));
    if (new_node == NULL) {
        perror("Not enough memory to add element!");
        exit(-1);
    }
    
    new_node->data = new_data;
    new_node->next = curr;
    if (prev == NULL) {
        /* Adica n == 0. */
        list->head = new_node;
    } else {
        prev->next = new_node;
    }

    if (new_node->next == NULL) {
        list->tail = new_node;
    }

    list->size++;
}

Node* remove_nth_node(LinkedList *list, int n) {
    Node *prev, *curr;

    if (list == NULL) {
        return NULL;
    }

    if (list->head == NULL) { /* Lista este goala. */
        return NULL;
    }

    /* n >= list->size - 1 inseamna eliminarea nodului de la finalul listei. */
    if (n > list->size - 1) {
        n = list->size - 1;
    } else if (n < 0) {
        return NULL;
    }

    curr = list->head;
    prev = NULL;
    while (n > 0) {
        prev = curr;
        curr = curr->next;
        --n;
    }

    if (prev == NULL) {
        /* Adica n == 0. */
        list->head = curr->next;
    } else {
        prev->next = curr->next;

        if (prev->next == NULL) {
            list->tail = prev;
        }
    }

    list->size--;
    return curr;
}

int get_size(LinkedList *list) {
    if (list == NULL) {
        return -1;
    }

    return list->size;
}

void free_list(LinkedList **pp_list) {
    struct Node *currNode;

    if (pp_list == NULL || *pp_list == NULL) {
        return;
    }

    while(get_size(*pp_list) > 0) {
        currNode = remove_nth_node(*pp_list, 0);
        free(currNode);
    }

    free(*pp_list);
    *pp_list = NULL;
}

void print_int_linkedlist(LinkedList *list) {
    Node *curr;

    if (list == NULL) {
        return;
    }

    curr = list->head;
    while (curr != NULL) {
        printf("%d ", *((int*)curr->data));
        curr = curr->next;
    }

    printf("\n");
}

void print_string_linkedlist(LinkedList *list) {
    Node *curr;

    if (list == NULL) {
        return;
    }

    curr = list->head;
    while (curr != NULL) {
        printf("%s ", (char*)curr->data);
        curr = curr->next;
    }

    printf("\n");
}



void init_list_graph(ListGraph *graph, int nodes) {
    graph->nodes = nodes;
    graph->neighbors = calloc(nodes, sizeof(LinkedList));

    if (graph->neighbors == NULL) {
        perror("Not enough memory to initialize the adjacency list!");
        exit(-1);
    }

    for (int i = 1; i <= nodes; ++i) {
        graph->neighbors[i] = malloc(sizeof(LinkedList));

        if (graph->neighbors[i] == NULL) {
            perror("Not enough memory to initialize the adjacency list!");
            exit(-1);
        }
        init_list(graph->neighbors[i]);
    }
}

void add_edge_list_graph(ListGraph *graph, int src, int *dest) {
    add_nth_node(graph->neighbors[src], (1 <<30), dest);
}

int has_edge_list_graph(ListGraph *graph, int src, int dest) {
    Node *head = graph->neighbors[src]->head;
    int crt_node;

    while (head != NULL) {
        crt_node = *(int *)head->data;

        if (crt_node == dest) {
            return 1;
        }
        head = head->next;
    }

    return 0;
}

LinkedList* get_neighbours_list_graph(ListGraph *graph, int node) {
    return graph->neighbors[node];
}

void remove_edge_list_graph(ListGraph *graph, int src, int dest) {
    Node *head = graph->neighbors[src]->head;
    int node_index = 0;
    int crt_node = 0;

    while (head != NULL) {
        crt_node = *(int *)head->data;

        if (crt_node == dest) {
            remove_nth_node(graph->neighbors[src], node_index);
            return;
        }
        head = head->next;
        ++node_index;
    }
}

void clear_list_graph(ListGraph *graph) {
    for (int i = 0; i < graph->nodes; ++i) {
        free_list(&graph->neighbors[i]);
    }
    free(graph->neighbors);
}

void init_q(Queue *q) {
    q->list = malloc(sizeof(LinkedList));
    if (q == NULL) {
        perror("Not enough memory to initialize the queue!");
        exit(-1);
    }

    init_list(q->list);
}

int get_size_q(Queue *q) {
    return q->list->size;
}

int is_empty_q(Queue *q) {
    return get_size_q(q) == 0;
}

void* front(Queue *q) {
    if (q == NULL || q->list == NULL) {
        return NULL;
    }

    return q->list->head->data;
}

void dequeue(Queue *q) {
    struct Node *node;
    if (q == NULL || q->list == NULL) {
        return;
    }

    node = remove_nth_node(q->list, 0);
    free(node);
}

void enqueue(Queue *q, void *new_data) {
    add_nth_node(q->list, q->list->size, new_data);
}

void clear_q(Queue *q) {
    struct Node *node;
    while (!is_empty_q(q)) {
        node = remove_nth_node(q->list, 0);
        free(node);
    }
}

void purge_q(Queue *q) {
    clear_q(q);
    free(q->list);
}




void dfs_list_graph(ListGraph *lg, int node, int *visited, Queue *q) {
    Node *pnt;
    int *N = malloc(sizeof(int));
    *N = node;
    visited[node] = 1;

    //if (lg->neighbors[node]->head == NULL) return;
    pnt = lg->neighbors[node]->head;
    enqueue(q, N);
    while (pnt != NULL) {
        if (visited[*(int*)pnt->data] == 0) {
            dfs_list_graph(lg, *(int*)pnt->data, visited, q);
        }
        pnt = pnt->next;
    }
}


int main() {
    int nodes, edges, *visited;
    int nodes_index[MAX_NODES];
    int x[MAX_NODES], y[MAX_NODES];
    ListGraph *lg = malloc(sizeof(ListGraph));
    Queue *q = malloc(sizeof(Queue));
    FILE *in, *out;

    in = fopen("sortaret.in", "rt");

    fscanf(in, "%d %d", &nodes, &edges);
    init_list_graph(lg, nodes);
    for (int i = 1; i <= nodes; ++i) {
        nodes_index[i] = i;
    }

    for (int i = 1; i <= edges; ++i) {
        fscanf(in, "%d %d", &x[i], &y[i]);
        add_edge_list_graph(lg, x[i], &y[i]);
    }

    fclose(in);
    out = fopen("sortaret.out", "wt");
    
    init_q(q);
    visited = calloc(nodes, sizeof(int));

    for (int i = 1; i <= nodes; i++) {
        if (visited[i] == 0) {
            dfs_list_graph(lg, i, visited, q);
        }
    }

    while (!is_empty_q(q)) {
        fprintf(out, "%d ", *(int*)front(q));
        dequeue(q);
    }
    fprintf(out, "\n");

    fclose(out);


    return 0;
}