import java.util.Scanner;

public class GCD {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.print("Please enter a number: ");
        int a = scan.nextInt();
        System.out.print("Please enter a number: ");
        int b = scan.nextInt();
        System.out.println(gcd(a, b));
    }

    public static int gcd(int a, int b) {
        if (a < b) {
            int c = b;
            b = a;
            a = c;
        }
        while (a != 0 && b != 0) {
            int c = b;
            b = b % a;
            a = c;
        }
        return a + b;
    }
}