import java.util.Scanner;

public class Gcd {
   public static void main(String[] args) {
      Scanner input = new Scanner(System.in);
       System.out.println("plz enter two enteger number:");
      long a = input.nextLong();
      long b = input.nextLong();
      long r = a%b;
      while(r != 0){
         a = b;
         b = r;
         r = a%b;
      }
      System.out.println("gcd is : " + b);
   }
}