#include <stdio.h>
#include <vector>

using namespace std;

FILE *f,*s;

int m,n,x,y,v2[100005],v3[100005],v4[100005];

vector<int> v1[100005];

void DFS(int x)
{
	for(int i=0;i<=v1[x].size();i++)
	{
		if(!v2[v1[x][i]])
		{
			v2[v1[x][i]]=1;
			
			y++;
			
			v3[y]=x;
			v4[y]=v1[x][i];
			
			DFS(v1[x][i]);
			
		}	
	}	
}

int main()
{
	f=fopen("mesaj4.in","r");
	s=fopen("mesaj4.out","w");
	
	fscanf(f,"%d %d",&m,&n);
	
	for(int i=1;i<=n;i++)
	{
		scanf("%d %d",&x,&y);
		
		v1[x].push_back(y);
		v1[y].push_back(x);
	}	
	
	y=0;
	
	v2[1]=1;
	
	DFS(1);
	
	fclose(s);
	
	return 0;
}