#include <bits/stdc++.h>
using namespace std;

int main() {
	int64_t v, t, p; cin >> v >> t >> p;
	int64_t ok = 0, ng = 5e18;
	while(abs(ok - ng) > 1) {
		int64_t mid = (ok + ng) / 2;
		if(mid - (v * p + mid / t) <= v) {
			ok = mid;
		} else {
			ng = mid;
		}
	}
	cout << ok + 1 << '\n';
	return 0;
}