#include<iostream>
#include<vector>
#include<algorithm>
typedef long long ll;
using namespace std;


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