using System;

public class Program

{

    public static void Main()

    {

        int a,b,hcf = 1;

        Console.WriteLine("Enter two numbers: ");

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

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

        if(a > b)

        {

          a = a + b;

          b = a - b;

          a = a - b;

        }

        for(int i = 1;i <= a/2;i++)

        {

         if(a % i == 0)

         {

          if(b % i == 0)

          {

           hcf = i;

          }

         }

        }

        Console.Write("HCF is {0}",hcf);

    }

}