UVa 10491 - Cows and Cars

// UVa 10491 - Cows and Cars

#include <iostream>
#include <stdio.h>
using namespace std;

int main() {

	int cows, cars, shows;

	while (cin >> cows >> cars >> shows) {
		double n = cows + cars;

		double cow_prop = cows / n;
		double car_prop = cars / n;

		double fst = (cars - 1) / (n - shows - 1);
		double snd = (cars) / (n - shows - 1);

		double sol = fst * car_prop + snd * cow_prop;
		printf("%.5f\n", sol);
	}

	return 0;
}