using System;

​

// http://www.csharpstar.com/csharp-program-to-check-whether-the-entered-number-is-an-armstrong-number-or-not/

public class Program

{

    public static void Main()

    {

        int n = 371;

        var isArmstrong = IsArmstrong(n);

        Console.WriteLine(isArmstrong);

    }

    private static bool IsArmstrong(int n)

    {

        if (n < 100 || 999 < n)

        {

            return false;

        }

        int first = n % 10;

        Console.Write(first);

        int second = (n - first) / 10 % 10;

        Console.Write(second);

        int third = (n - second * 10 - first) / 100;

        Console.Write(third);

        return Math.Pow(first, 3) + Math.Pow(second, 3) + Math.Pow(third, 3) == n;

    }

}