//Elfus <3 tractoare
//To be continued..

#include <stdio.h>
#include <vector>
#include <string.h>
#include <algorithm>
#include <iostream>

using namespace std;

vector <int> ini[32100], GTini[32100], G[32100];
bool vis[32100];
int N, M, cnt, st[32100];
int iniToG[32100];

void dfs(int nod) {
    vis[nod] = 1;
    vector <int> :: iterator it;
    for (it = GTini[nod].begin(); it != GTini[nod].end(); ++it)
        if (!vis[*it])
            dfs(*it);
    st[++st[0]] = nod;
}

void dfs2(int nod) {
    vis[nod] = 1;
    iniToG[nod] = cnt;
    vector <int> :: iterator it;
    for (it = ini[nod].begin(); it != ini[nod].end(); ++it)
        if (!vis[*it])
            dfs2(*it);
        else
            if (iniToG[nod] != iniToG[*it])
                G[iniToG[nod]].push_back(iniToG[*it]);
}

void buildDAG() {
    for (int i = 1; i <= N; ++i)
        if (!vis[i])
            dfs(i);
    memset(vis, 0, sizeof(vis));
    for (int i = st[0]; i >= 1; --i)
        if (!vis[st[i]]) {
            ++cnt;
            dfs2(st[i]);
        }
    N = cnt;
    for (int i = 1; i <= N; ++i) {
        vector <int> :: iterator it;
        it = unique(G[i].begin(), G[i].end());
        G[i].resize(distance(G[i].begin(), it));
    }
}

int root, deg[32100];

void findRoot() {
    for (int i = 1; i <= N; ++i) {
        vector <int> :: iterator it;
        for (it = G[i].begin(); it != G[i].end(); ++it)
            ++deg[*it];
    }
    for (int i = 1; i <= N; ++i)
        if (deg[i] == 0)
            root = i;
}

vector <int> treeEdge[31000], backEdge[31000];
int E[2 * 31000], Lev[2 * 31000], First[31000];

void dfs3(int nod, int level) {
    E[++E[0]] = nod;
    Lev[E[0]] = level;
    First[nod] = E[0];
    vector <int> :: iterator it;
    for (it = G[nod].begin(); it != G[nod].end(); ++it)
        if (!First[*it]) {
            dfs3(*it, level + 1);
            treeEdge[nod].push_back(*it);
            E[++E[0]] = nod;
            Lev[E[0]] = level;
        } else
            backEdge[nod].push_back(*it);
}

int main() {
    freopen("obiective.in", "r", stdin);
    freopen("obiective.out", "w", stdout);

    scanf("%d%d", &N, &M);
    for (int i = 1; i <= M; ++i) {
        int xx, yy;
        scanf("%d%d", &xx, &yy);
        ini[xx].push_back(yy);
        GTini[yy].push_back(xx);
    }

    buildDAG();
    findRoot();
    dfs3(root, 1);

    return 0;
}