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