#include<stdio.h>   
long a,b;   
long euclid(long a,long b){   
                if(b==0) return a;   
                  else return euclid(b,a%b);   
                     }   
int main()   
{   
 freopen("euclid2.in","r",stdin);   
 freopen("euclid2.out","w",stdout);   
 scanf("%ld %ld",&a,&b);   
 a=euclid(a,b);   
 printf("%ld",a);   
 fclose(stdout);   
 return 0;   
}