#include <iostream>
#include <set>
#include <queue>
#include <cassert>
#define repeat(i,n) for (int i = 0; (i) < (n); ++(i))
using namespace std;
template <class T> void setmin(T & a, T const & b) { if (b < a) a = b; }
template <class T> using reversed_priority_queue = priority_queue<T, vector<T>, greater<T> >;
template <typename T> T gcd(T a, T b) { while (a) { b %= a; swap(a, b); } return b; }
const int inf = 1e9+7;
int main() {
    int a, b, t; cin >> a >> b >> t;
    int ans = inf;
    if (b < 100) {
        set<int> used;
        reversed_priority_queue<int> que;
        que.push(0);
        while (not que.empty()) {
            int i = que.top(); que.pop();
            used.erase(i);
            if (i >= t) { setmin(ans, i); break; }
            if (i >= 10000000) break;
            setmin(ans, i + (t - i + a-1)/a*a);
            setmin(ans, i + (t - i + b-1)/b*b);
            if (ans == t) break;
            if (not used.count(i + a)) { used.insert(i + a); que.push(i + a); }
            if (not used.count(i + b)) { used.insert(i + b); que.push(i + b); }
        }
    } else {
        for (int i = 0; i <= t; i += b) {
            setmin(ans, i + (t - i + a-1)/a*a);
        }
    }
    cout << ans << endl;
    return 0;
}