#line 1 "main.cpp"
#include <iostream>
#include <numeric>

using namespace std;
using lint = long long;
constexpr lint INF = 1LL << 61;

void solve() {
    lint a, b, k;
    cin >> a >> b >> k;

    lint ok = INF, ng = 0;
    while (ok - ng > 1) {
        auto mid = (ok + ng) / 2;

        auto cnt = mid / a + mid / b - mid / lcm(a, b);
        if (cnt >= k) {
            ok = mid;
        } else {
            ng = mid;
        }
    }

    cout << ok << "\n";
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    solve();

    return 0;
}