#include <cmath>
#include <map>
#include <string>
#include <vector>
#include <set>
#include <algorithm>
#include <iostream>
using namespace std;
#define repi(_I, _B, _E) for(int _I = (_B); (_I) < (_E); ++ (_I))
#define rep(_I, _N) for(int _I = 0; (_I) < (_N); ++ (_I))
#define all(_X) (_X).begin(), (_X).end()

int a, b, t;
int main() {
	cin >> a >> b >> t;

	int c = a + b;
	int ccnt = t / c;
	int u = t - ccnt * c;

	int m = 2000000000;
	int acnt = ((u + a - 1) / a);
	int bcnt = ((u + b - 1) / b);
	m = min(m, (ccnt + 1) * c);
	m = min(m, acnt * a + ccnt * c);
	m = min(m, bcnt * b + ccnt * c);
	cout << m << endl;

	return 0;
}