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