// I SELL YOU...! 
#include<iostream>
#include<vector>
#include<algorithm>
#include<functional>
#include<queue>
#include<chrono>
#include<iomanip>
#include<map>
#include<set>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
using TP = tuple<ll,ll,ll>;
void init_io(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(18);
}
signed main(){
  init_io();
  ll a,b;
  cin >> a >> b;
  if(a*b<0){
    a = abs(a);
    b = abs(b);
    if(b%a==0){
      cout << b/a<<endl;
    }else cout << "-1\n";
  }else if(a*b>0){
    cout << "-1\n";
  }else{
    if(b==0){
      cout << 1 << endl;
    }else{
    cout << "-1\n";
    }
  }
}