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

namespace ConsoleApplication8
{
    class Program
    {
        static void Main(string[] args)
        {
            int N = Convert.ToInt32(Console.ReadLine());
            int A = Convert.ToInt32(Console.ReadLine());
            int B = Convert.ToInt32(Console.ReadLine());
            if (N >= 1 && 100 >= N)
                if (A >= 1 && 100 >= A)
                    if (B >= 1 && 100 >= B)
                    {
                Console.WriteLine(N * A * B * 2);
            }
        }
    }
}

1) Here is task fragment: "The only line contains integers...."
You are reading 3 lines.

2) if (N) if (A) if (B) {...} - else what?
Any difference how exactly your program fail in "else" case?
I think you should skip parameters check or fail in some specific way - visible and different from regular mistake.

Edited by author 16.11.2016 16:53