//poramnena parovi broevi

package com.codewithDZM;

import java.util.Scanner;
import java.util.Random;
public class Main
{


    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        for (int i = 1; i < n; i++)
        {
            for (int j = i + 1; j <= n; j++)
            {
                System.out.printf("%2d:%2d ", i ,j);

            }
            System.out.println();
        }


    }
}