#include <cstdio>
#include <algorithm>
#include <vector>

using namespace std;

FILE *f=fopen("sortaret.in","r"),*s=fopen("sortaret.out","w");

int n, m, aux, i, j;

vector<int> v;


int main()
{
	fscanf(f,"%d %d",&n,&m);
	
	aux=m;
	
	while(aux--)
	{
		fscanf(f,"%d %d",&i,&j);
		v.push_back(i);
		v.push_back(j);
	}
	
	sort(v.begin(),v.end()+1);
	
	aux=v.front();
	
	fprintf(s,"%d ",aux);
	
	for(i=1;i<v.size();i++)
	{
		if(v[i]!=aux)
			fprintf(s,"%d ",v[i]);
		aux=v[i];
	}
	
	
	fclose(s);
	
	
	return 0;
}