#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",&a);
    scanf("%d",&b);
    
    if(a<=0 || b<=0)
    printf("invalid input\n");
    return 0;
    
}
printf("%d\n",gcd(a,b));
return 0;
}