#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	long long a, b, c; cin >> a >> b >> c; 
	vector<long long>ans;
	/*rep(i,1000000) {
		long long x = i;
		x *= a;
		if (x > b)x -= b;
		if (x == c)ans.push_back(i);
	}*/
	if (b > c) {
		long long x = c;
		long long y = c + b;
		if (0 == x % a)ans.push_back(x / a);
		if (0 == y % a)ans.push_back(y / a);
	}
	else {
		long long x = c;
		if (0 == x % a)ans.push_back(x / a);
	}
	if (ans.empty())ans.push_back(-1);
	rep(i, ans.size())cout << ans[i] << endl;
	return 0;
}