using System;

public class Exercise21 

​

{

    public static void Main()

    {   

        int num1=0, num2=0;

        try

        {

        Console.WriteLine("Write a C# program to check the sum of the two given integers and return true if one of the integer is 20 or if their sum is 20.");  

        Console.WriteLine(" Input first number: ");

        num1= Convert.ToInt32(Console.ReadLine ());

        Console.WriteLine(" Input second number: ");

        num2= Convert.ToInt32(Console.ReadLine ());

        Console.WriteLine( num1 == 20 || num2 == 20 || (num1 + num2 == 20));

        }

        catch (FormatException)

        {

            Console.WriteLine("No has ingresado un número valido.");

        }

    }

    }

​