import java.util.Scanner;

public class Main {
	public static long gcd(long n,long r){
		return r==0?n:gcd(r,n%r);
	}

	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long a=sc.nextInt();
		long b=sc.nextInt();
		System.out.println(gcd(a,b));
	}
}