/*
 * sortaret.cpp
 *
 *  Created on: Jun 23, 2017
 *      Author: andreir
 */
#include <fstream>
#include <vector>
#include <queue>
#include <iostream>
using namespace std;

ifstream in("sortaret.in");
ofstream out("sortaret.out");

int const NMAX = 50005;
int const MMAX = 100005;

int N, M, len;
int GradExt[NMAX];
queue<int> Q;
vector<int> V[NMAX];

void Sort() {
    int i, j, x;
    for (x = 1; x <= N; x++)
        if (GradExt[x] == 0) {
            Q.push(x);
            out << x;
        }

    for (i = 1; i <= N; i++) {
        x = Q.front();
        Q.pop();
        for (j = 0; j < (int) V[x].size(); j++) {
            GradExt[V[x][j]]--;
            if (GradExt[V[x][j]] == 0) {
                Q.push(V[x][j]);
                out << V[x][j];

            }

        }
    }
}

void Read() {
    int x, y;
    in >> N >> M;
    for (int i = 0; i <= N; i++) {
        in >> x >> y;
        V[x].push_back(y);
        GradExt[y]++;
    }
}

int main() {
    Read();
    Sort();
}