#include 
#include 
using namespace std;
int n, m;
vector graph[105];
bool visited[105];

void dfs(int node) {
    visited[node] = true;
    cout << node << endl;
    for(int i = 0; i < graph[node].size(); i++) {
        int sosed = graph[node][i];
        if(!visited[sosed]) {
            dfs(sosed);
        }
    }
}
int main()
{
    cin >> n >> m;
    for(int i = 0; i < n; i++) {
        visited[i] = false;
    }
    for(int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    dfs(0);
   return 0;
}