#include <bits/stdc++.h>

using namespace std;

const int N = 100000 + 5;
const int M = 500000 + 5;

int n, m;
int x[M], y[M];
bool seen[M];
vector <int> id[N];

vector <int> way;

void dfs(int nod)
{
    while (!id[nod].empty())
    {
        int i = id[nod].back();
        id[nod].pop_back();
        if (seen[i] == 0)
        {
            seen[i] = 1;
            dfs(x[i] + y[i] - nod);
        }
    }
    way.push_back(nod);
}

int main()
{
    freopen ("ciclueuler.in", "r", stdin);
    freopen ("ciclueuler.out", "w", stdout);
    cin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        cin >> x[i] >> y[i];
        id[x[i]].push_back(i);
        id[y[i]].push_back(i);
    }
    dfs(1);
    way.pop_back();
    for (auto &x : way)
    {
        cout << x << " ";
    }
    cout << "\n";
}