#include <iostream>
#include <queue>
using namespace std;

const int maxn = 100000;
vector<int> graph[maxn];
int main()
{
    int n, m;
    cin >> n >> m;
    
    for(int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < graph[i].size(); j++) {
            cout << i << " <--> " << graph[i][j] << endl;
        }
    }

    return 0;

}