#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 5;
vector<pair<int, int>> adj[N];
vector<int> vis(N, 0);
vector<int> path;
void dfs(int u) {
while (!adj[u].empty()) {
auto [v, i] = adj[u].back();
adj[u].pop_back();
if (vis[i]) continue;
vis[i] = 1;
dfs(v);
}
path.push_back(u);
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m;
cin >> n >> m;
for (int i = 0; i < m; i++) {
int a, b;
cin >> a >> b;
adj[a].push_back({b, i});
adj[b].push_back({a, i});
}
dfs(1);
reverse(path.begin(), path.end());
for (int i = 0; i < (int)path.size() - 1; i++) {
cout << path[i] << ' ';
}
cout << '\n';
return 0;
}
