#include <bits/stdc++.h>
using namespace std;

#define N 100010
int n, m, to[N], from[N];
vector <int> sol, v[N];

struct edge{
    int a, b, c;
} M[5*N];

int nxt(int nod, int i){
    if (nod == M[i].a) return M[i].b;
    return M[i].a;
}

void dfs(int q){
    for (auto i: v[q]){
        if (M[i].c) M[i].c = 0, dfs(nxt(q, i));
    }
    sol.push_back(q);
}

int main(){
    ifstream cin ("ciclueuler.in");
    ofstream cout ("ciclueuler.out");
    cin >> n >> m;
    for (int i=1; i<=m; i++){
        int x, y;
        cin >> x >> y;
        v[x].push_back(i);
        v[y].push_back(i);
        M[i] = {x, y, 1};
    }
    dfs(1);
    for (auto it: sol) cout << it << " ";
    return 0;
}