#include <bits/stdc++.h>
using namespace std;
int main(){
  int A, B, C;
  cin >> A >> B >> C;
  vector<int> ans;
  if (C <= B){
    if (B % A == 0){
      ans.push_back(B / A);
    }
  }
  if ((B + C) % A == 0){
    ans.push_back((B + C) / A);
  }
  if (ans.empty()){
    cout << -1 << endl;
  } else {
    for (int x : ans){
      cout << x << endl;
    }
  }
}