#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
#include <iostream>

using namespace std;

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

vector<int> v[50010];
bitset<100010> viz;
queue<int> q;
int n, m, nod_start;

void bfs(int nod_start) {
    fout << nod_start << " ";
    for (auto it:v[nod_start])
        if (!viz[it]) {
            viz[it]=1;
            bfs(it);
        }
}

int main() {
    fin >> n >> m;
    int a, b;
    fin >> a >> b;
    nod_start = a;
    viz[nod_start]=1;
    v[a].push_back(b);
    while (fin >> a >> b)
        v[a].push_back(b);

    bfs(nod_start);

    return 0;

}