#include <cstdio>
#include <vector>
#include <deque>
using namespace std;

vector< pair<int,int> > lista[100005];
deque<int> q;
bool viz[100005];

void eulerian(int nod)
{
	while(lista[nod].size())
	{
		// daca vecinul nu e vizitat ( adica nu am folosit muchia )
		if( viz[lista[nod].back().first]==0)
		{
			viz[lista[nod].back().first]=1; // vizitez vecinul viz[indice]
			int next_nod=lista[nod].back().second; // scot
			
			lista[nod].pop_back();
			eulerian(next_nod);
		}
			else
				lista[nod].pop_back();
	}
	q.push_back(nod);
	return;
}

int main()
{
	int n,m;
	freopen("ciclueuler.in","r", stdin);
	freopen("ciclueuler.out","w", stdout);
	scanf("%d %d",&n,&m);
	for(int i=1;i<=m;i++)
	{
		int x,y;
		scanf("%d %d",&x,&y);
		//printf("%d %d\n",x,y);
		lista[x].push_back(make_pair(i,y));
		lista[y].push_back(make_pair(i,x));
	}
	eulerian(1);
	q.pop_back();
	while(q.size())
	{
		printf("%d ",q.front());
		q.pop_front();
	}
	return 0;
}