#include <stdio.h>

int gcd(int a, int b) {
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

int main() {
    int a, b;
    
    if (scanf("%d", &a) != 1 || sacnf("%d", &b) != 1) {
        printf("Invalid input\n");
        return 1;
    }
    
    if (a <= 0 || b <= 0) {
        printf("Invalid input\n");
    } else {
        int result = gcd(a, b);
        printf("%d\n", result);
    }
    
    return 0;
}