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

const int maxN = 100;
vector<int> adj[maxN];
bool visited[maxN];

void dfs (int node) {
	//~ cout << " => " << node;
	visited[node] = true;

	for (auto child : adj[node]) {
		if (visited[child] == false) {
			dfs(child);
		}
	}
}

int main () {
	 ios::sync_with_stdio(false);
	 cin.tie(nullptr);
	 cout.tie(nullptr);
	 int n = 7;
	 int m = 6;
	 for (int i = 1; i <= m; ++i) {
		 int u,v;
		 cin >> u >> v;
		 adj[u].push_back(v); //u er adj te v ke rakhtesi
		 adj[v].push_back(u); //v er adj te u ke rakhtesi
	 }
	 dfs(1);
}


//~ 1 2
//~ 2 4
//~ 2 5
//~ 1 3
//~ 3 6
//~ 3 7