Test_Number

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test_Numbers
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int m = int.Parse(Console.ReadLine());
            int stop = int.Parse(Console.ReadLine());

            int combinationsSum = 0;
            int count = 0;
            bool isNumber = false;

            for (int i = n; i >=1; i--)
            {
                for (int k = 1; k <= m; k++)
                {
                  	combinationsSum += + 3 * (i * k);
                    count++;
                    if (combinationsSum >= stop)
                    {
                        isNumber = true;
                        Console.WriteLine($"{count} combinations");
                        Console.WriteLine($"Sum: {combinationsSum} >= {stop}");
                        return;
                    }

                }

            }
            if (!isNumber)
            {
                Console.WriteLine($"{count} combinations");
                Console.WriteLine($"Sum: {combinationsSum}");
            }
        }
    }
}