#include<bits/stdc++.h>
using namespace std;
vector<int> book[100009];
int n,m,ans[100010],vis[100010];
priority_queue<int,vector<int>,greater<int>> q;
int main()
{
	cin>>n>>m;
	for(int i=1;i<=m;i++)
	{
		int u,v;
		cin>>u>>v;
		book[u].push_back(v); 
		book[v].push_back(u); 
	}
	q.push(1);
	int sum=0;
	while(!q.empty())
	{
		int h=q.top();
		q.pop();
		vis[h]=1;
		ans[sum++]=h;
		for(int i=1;i<=book[h].size();i++)
		{
			int p=book[h].at(i);
			if(vis[p]!=1)
			{
				vis[p]=1; 
				q.push(p);
			}
		}
	} 
	for(int i=1;i<=n;i++) cout<<ans[i]; 
	return 0;
}