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