#include <bits/stdc++.h>

long gcd(long a, long b) {
  return b == 0 ? a : gcd(b, a % b);
}

long mul(long a, long b, long m) {
  long res = 0;
  while( b != 0LL ) {
    if( b & 1 ) res = (res + a) % m;
    b >>= 1;
    a = (a << 1) % m;
  }
  return res;
}

int main() {
  long a, b;
  scanf("%ld %ld", &a, &b);
  long x = a + b;
  long y = mul(a, b, a + b);
  printf("%ld\n", gcd(x, y));  

  return 0;
}