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

int main() {
    
    int i, j;
    const int N = 4;
    int array[N][N] = {
        {1, 2, 3, 4},
        {3, 4, 5, 6},
        {7, 8, 9, 1},
        {2, 3, 4, 5}
    };
    
    
    for (i = 0; i < N; i++) {
        for (j = 0; j < i; j++) {
            cout << array[i][j] << " ";
        }
    }
    cout << endl;

    
    return 0;
}