#include <iostream>
#include <vector>
#include <algorithm> // for sort
 
using namespace std;
 
struct edge {
    int dau, cuoi, w;
};
 
vector<int> ke[1001];
 
int main() {
    int n, m; 
    cin >> n >> m;
 
    // Initialize variables before using them
    int x, y;
 
    for(int i = 0; i < m; i++) {
        cin >> x >> y;
        ke[x].push_back(y);
        ke[y].push_back(x);
    }
 
    for(int i = 1; i <= n; i++) {
        sort(ke[i].begin(), ke[i].end());
        cout << i << " : "; 
        for(int neighbor : ke[i]) {
            cout << neighbor << " ";
        }
        cout << endl;
    }
 
    return 0;
}
 

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5 4
2 5
4 1
4 2
4 3