#include <iostream>
using namespace std;

int main() {
    cout << "Enter a Number(Row) : ";
    int n;
    cin >> n;
    cout << endl;
    
    int row = 1;
    
    while(row <= n){
        int col = row;
        // can use third variable(counting) to do this question
        // this is more optimized in terms of space.
        while( col < row * 2){
            cout << col << " ";
            col += 1;
        }
        cout << endl;
        row += 1;
    }
}