#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using llu = long long unsigned;

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

    int ret = 0;
    for (int i=1; i*a<x; ++i) {
        ret = i;
    }
    if (ret*a < x) { ret++; }

    cout << ret * b << endl; return 0;
}