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

int main(){
  int A, B, C;
  cin >> A >> B >> C;
  
  vector<int> ans;
  if(C % A == 0 && C <= B) ans.emplace_back(C / A);
  if((B + C) % A == 0) ans.emplace_back((B + C) / A);
  
  if(ans.empty()) cout << -1;
  else for(auto x : ans) cout << x << endl;
}