#include<stdio.h>
int gcd(int a, int b){
while (b !=0){
int temp = b;
b = a % b;
a = temp;
}
return a;
}
int main(){
int a, b;
if (scanf(%d %d" , &a, &b) !=2){
   printf("Invalid input\n");
}else{
printf("%d\n",gcd(a, b));
}
return 0;
}