#include <iostream>
int64_t gcd(int64_t a, int64_t b) {
    if(b==0)
        return a;
    a=a%b;
    return gcd(b,a);
}
int main() {
  int64_t a, b;
  std::cin >> a >> b;
  std::cout << gcd(a, b) << std::endl;
  return 0;}