#include <bits/stdc++.h>

using namespace std;

ifstream f("ciclueuler.in");
ofstream g("ciclueuler.out");

int N, M, k, x, y;
bool a[10003][10003];

int sol[500003];
void df(int x) {
    for(int i = 1; i <= N; i++) {
        if(a[x][i] == 1) {
            a[x][i] = a[i][x] = 0;
            sol[++k] = i;
            df(i);
        }
    }
}
int main()
{
    f >> N >> M;
    for(int i = 1; i <= M; i++) {
        f >> x >> y;
        a[x][y] = a[y][x] = 1;
    }
    df(1);
    g << "1 ";
    for(int i = 1; i <= k; i++)
        g << sol[i] << " ";
    return 0;
}