# include <vector>
# include <stdio.h>
# include <list>
using namespace std;
list <int> q;
vector <int> v[100010];
int x,y,i,n,m,nr;
int main()
{
	freopen("ciclueuler.in","r",stdin);
	freopen("ciclueuler.out","w",stdout);
	scanf("%d %d\n",&n,&m);
	for (i=1; i<=m; i++)
	{
		scanf("%d %d\n",&x,&y);
		v[x].push_back(y);
		v[y].push_back(x);
	}
	
	for (i=1; i<=n; i++)
		if (v[i].size()%2==1)
			return 0;
	nr=0;
	q.push_front(1);
	while(!q.empty())
	{
		x=q.front();
		if (v[x].empty())
		{
			nr++;
			q.pop_front();
			if (nr<=m)
			printf("%d ",x);
			continue;
		}
		else
		{
			y=v[x].back();
			q.push_front(y);
			v[x].pop_back();
			for (vector <int> :: iterator it=v[y].begin(); it<v[y].end(); it++)
				if (*it==x) { v[y].erase(it); break; }
		}
	}
	printf("\n");
	return 0;
}