#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");
        return 0;
    }
    printf("%d",gcd(a,b));
    return 0;
}