#include <iostream>
using namespace std;

int main() {
    int A, B, C;
    cin >> A >> B >> C;

    bool found = false;
    for (int N = 1; N <= C; N++) {
        int temp = N;
        temp *= A;
        temp -= B;
        if (temp == C && temp > 0) {
            cout << N << endl;
            found = true;
        }
    }
    if (!found) {
        cout << -1 << endl;
    }
    return 0;
}