#include <iostream>

using lint = long long;
constexpr lint INF = 1LL << 60;

void solve() {
    lint v, t, p;
    std::cin >> v >> t >> p;

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

        if (mid - (mid + t - 2) / t - p * v <= v) {
            ok = mid;
        } else {
            ng = mid;
        }
    }

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

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

    solve();

    return 0;
}