#include <bits/stdc++.h>
using namespace std;

long long n, m, vis[6010];
vector <int> d[5005];

void dfs(int x)
{
	cout << x << " ";
	vis[x] = 1;
	for (int i = 0; i < d[x].size(); i++)
		if (vis[d[x][i]] == 0) dfs(d[x][i]);
	return ;
}

int main()
{
	freopen("travel.in", "r", stdin);
	freopen("travel.out", "w", stdout);
	cin >> n >> m;
	for (int i = 1; i <= m; i++)
	{
		int x, y;
		cin >> x >> y;
		d[x].push_back(y);
		d[y].push_back(x);
	}
	for (int i = 1; i <= n; i++)
		sort(d[i].begin(), d[i].end());
	dfs(1);
	return 0;
}

60pts，剩下的WA了