#include<iostream>
#include<vector> //to store data
#include<queue>

using namespace std;


int visited[13];
vector<int> graph[13];
 
void bfs(int start)
{
	queue<int> need_visit;
	
	need_visit.push(start);
	visited[start] = true;
	
	while(!need_visit.empty())
	{
		int x = need_visit.front();
		cout << x << " ";
		need_visit.pop();
		
		for(int i = 0; i < graph[x].size() ; ++i)
		{
			int y = graph[x][i];
			if(!visited[y])
			{
				need_visit.push(y);
				visited[y] = true;
			}
		}
	}
}
int main()
{
	graph[1].push_back(2);
	graph[2].push_back(1);
	
	graph[1].push_back(3);
	graph[3].push_back(1);
	
	graph[1].push_back(4);
	graph[4].push_back(1);
	
	graph[2].push_back(5);
	graph[5].push_back(2);

	graph[2].push_back(6);
	graph[6].push_back(2);
	
	graph[4].push_back(7);
	graph[7].push_back(4);
	
	graph[4].push_back(8);
	graph[8].push_back(4);
	
	graph[5].push_back(9);
	graph[9].push_back(5);

	graph[5].push_back(10);
	graph[10].push_back(5);	
		
	graph[7].push_back(11);
	graph[11].push_back(7);
	
	graph[7].push_back(12);
	graph[12].push_back(7);	
	
	bfs(1);
	
	return 0;
}