#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
	cin.tie(0); ios::sync_with_stdio(false);
	long long A, B, T;
	cin >> A >> B >> T;
	if (A >= T && B >= T) { cout << ((A > B) ? A : B) << endl; return 0; }
	else if (A >= T) { cout << A << endl; return 0; }
	else if (B >= T) { cout << B << endl; return 0; }
	long long ans = T + T + T;
	vector<vector<long long> > v(T / A + 10, vector<long long>(T / B + 10, 0));
	v[1][0] = A; v[0][1] = B;
	for (int i = 0; i < T / A + 3;i++) {
		for (int j = 0; j < T / B + 3;j++) {
			v[i][j] = A*i + B*j;
			if (v[i][j] >= T) { ans = min(ans, v[i][j]); }
			if (v[i][j] >= T + T) { break; }
		}
	}
	cout << ans << endl;return 0;
}