#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(x) x.begin(),x.end() 
typedef long long ll;
//using mint = modint;
using mint = modint998244353;
using P = pair<int, int>;

const ll INF=1LL<<60, dx[]={0,1,0,-1},dy[]={1,0,-1,0};
template <typename T> inline bool chmin(T& a,const T&b) {if(a>b){a=b; return 1;} return 0;}
template <typename T> inline bool chmax(T& a,const T&b) {if(a<b){a=b; return 1;} return 0;}

int main(){

    ll a,b,c;
    cin >> a >> b >> c;
    
    vector<ll> ans;
    if(b>=c) {
        if(c%a==0) ans.push_back(c/a);
    }
    if((b+c)%a==0) ans.push_back((b+c)/a);

    if(ans.size()) {
        for(auto i:ans) cout << i << endl;;
    } else {
        cout << -1 << endl;
    }

    return 0;
}