#include <bits/stdc++.h>
using namespace std;

using ll = long long;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  
  ll a, b;
  cin >> a >> b;
  
  if (b == 0) cout << "1\n";
  else if (a >= 0) cout << "-1\n";
  else if (a == -1) cout << "2\n";
  else cout << "-1\n";
}