import java.util.*;
 
class Main
{
	public static void main (String[] args) {
		Scanner in = new Scanner(System.in);
    	        long n, m;
    	        n = in.nextLong();
    	        m = in.nextLong();
    	        System.out.print(f(n, m));
	}
	static long f(long n, long m) {
		if (n % m == 0) return m;
	        if (m % n == 0) return n;
	        if (m > n) return f(m % n, n);
	        else return f(n % m , m);
	}
}