#include <iostream>
#include <vector>
#include <algorithm>

using namespace std; using ll=long long; const ll LNF=1e18; const int INF = 1e9+1; const ll M = 1e9+7;
typedef pair<int,int> P;

int main() {
  ll a,b; cin>>a>>b;
  if (b==0) {
    cout<<1<<endl;
    return 0;
  }
  else if (a>0) {
    cout<<-1<<endl;
    return 0;
  } else if (a==-1){
    cout<<2<<endl;
    return 0;
  } else {
    cout<<-1<<endl;
    return 0;
  }
}