#include <iostream>
using namespace std;
void ins() {}
template<class T,class... Rest>void ins(T& v,Rest&... rest){cin>>v;ins(rest...);}

int main() {
  int A, B;
  ins(A, B);

  if (A > 0 && B > 0) {
    cout << "-1\n";
    return 0;
  }
  if (B == 0) {
    cout << "1\n";
    return 0;
  }
  if (A == -1) {
    cout << "2\n";
    return 0;
  }
  cout << "-1\n";

  return 0;
}