#include<iostream>
using namespace std;
int main() {

	long long int a, b, c;
	double r,d;
	std::cin >> a;
	std::cin >> b;
	std::cin >> c;
	r = (double)(b - c) / (a - b);
	d = (double)b - r*a;
	std::cout << c*r + d;

}