#include <stdio.h>
#include <vector>
#include <list>
#define NMax 100010
using namespace std;

const char IN[]="ciclueuler.in",OUT[]="ciclueuler.out";

int N,M;
list<int> ad[NMax];
vector<int> sol;

void erase(int x,int y){

	for (typeof(ad[x].begin()) it=ad[x].begin();it!=ad[x].end();++it) if (*it==y)
	{
		ad[x].erase(it);
		break;
	}

	for (typeof(ad[y].begin()) it=ad[y].begin();it!=ad[y].end();++it) if (*it==x)
	{
		ad[y].erase(it);
		break;
	}
}

void euler(int x){

	int y;
	for(;ad[x].size();){
		y=*ad[x].begin();
		erase(x,y);
		euler(y);
	}
	sol.push_back(x);
}

int main()
{
	int i,x,y;
	freopen(IN,"r",stdin);
	scanf("%d%d",&N,&M);
	for (i=1;i<=M;++i)
	{
		scanf("%d%d",&x,&y);
		ad[x].push_back(y);
		ad[y].push_back(x);
	}

	euler(1);

	freopen(OUT,"w",stdout);
	for (i=0;i<(int)sol.size()-1;++i) printf("%d ",sol[i]);
	printf("\n");
	fclose(stdout);

	return 0;
}