#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

int n, m, nc = 0;
int c[500001];
int g[100001][100001];

void euler(int x)
{
	for(int urm = 1; urm <= n; ++urm)
	{
		if(g[x][urm])
		{
			g[x][urm] = 0,
			g[urm][x] = 0;
			euler(urm);
		}
		c[nc++] = x;
	}
}

int main()
{
	fin >> n >> m;
	int u, v;
	for(int i = 1; i <= m; ++i)
	{
		fin >> u >> v;
		g[u][v] = 1,
		g[v][u] = 1;
	}
	euler(1);
	for(int i = 1; i <= nc; ++i)fout << c[i] << ' ';
	return 0;
}