#include <cstdio>
#include <vector>
#define maxn 100100

using namespace std;

int n, m, a, b, i, j;
vector <int> g[maxn], muc[maxn];
bool vizm[5 * maxn];

void df(int nod) {
	int i;
	for (i = 0; i < g[nod].size(); i++) {
		if (!vizm[muc[nod][i]]) {
			vizm[muc[nod][i]] = 1;
			df(g[nod][i]);
			printf("%d ", nod);
		}
	}
}

int main() {
	freopen("ciclueuler.in", "r", stdin);
	freopen("ciclueuler.out", "w", stdout);

	scanf("%d%d", &n, &m);
	for (i = 1; i <= m; i++) {
		scanf("%d%d", &a, &b);
		g[a].push_back(b);
		g[b].push_back(a);
		muc[a].push_back(i);
		muc[b].push_back(i);
	}

	df(1);

	return 0;
}