using System;

//3

using System;

void PrintDivisors(int num)

{

    int k = 2;

    while (k <= num)

    {

        string divisors = ""; 

        int i = 2;

        while (i < k)

        {

            if (k % i == 0) 

            {

                divisors += i + " "; 

            }

            i++;

        }

        if (divisors != "") 

        {

            Console.WriteLine(k + ": " + divisors);  

        }

        else

        {

            Console.WriteLine(k + ":"); 

        }

        k++;

    }

}

PrintDivisors(12);

​