#include <bits/stdc++.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

int main() {
	int v = ri();
	int t = ri();
	int p = ri();
	__int128 l = (int64_t) v * (p + 1), r = (int64_t) v * (p + 1) * 3;
	while (r - l > 1) {
		__int128 m = l + ((r - l) >> 1);
		__int128 clearance = m -(int64_t) v * (p + 1);
		if (1 + (clearance - 1) * t < m) l = m;
		else r = m;
	}
	std::cout << (int64_t) l << std::endl;
	return 0;
}