using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("This program will calculate the GCD of two numbers. Please enter your two values");

       long num1 = long.Parse(Console.ReadLine());

       long num2 = long.Parse(Console.ReadLine());

       long ans = GCD (num1, num2);

       Console.WriteLine(ans);

    }

        static private long GCD(long a, long b)

        { long remainder;

        do

        {remainder = a%b;

            if(remainder !=0)

            {a = b;

             b = remainder;

            }

        } while(remainder >0);

        return b;

        }

​

    }