#include<stdio.h>
int gcd(int a, int b){
    if(b == 0){
        return a;
    }
    return gcd(b, a % b);
}
int main(){
    int a, b;
    scanf("%d %d", &a, &b);
    if(a <= 0 || b <= 0){
        printf("Invalid input\n"):\;
    }else{
        printf("%d\n", gcd(a, b));
    }
    return 0;
}