#include <bits/stdc++.h>
//#include <atcoder/all>

typedef unsigned long long ULLONG;
typedef long long LLONG;
static const LLONG MOD_NUM = 1000000007; //998244353;

template<class _T> static void get(_T& a) {
	std::cin >> a;
}
template<class _T> static void get(_T& a, _T& b) {
	std::cin >> a >> b;
}
template<class _T> static void get(_T& a, _T& b, _T& c) {
	std::cin >> a >> b >> c;
}
template <class _T> static _T tp_abs(_T a) {
	if (a < (_T)0) {
		a *= (_T)-1;
	}
	return a;
}

static void A();

int main()
{
	A();
	fflush(stdout);
	return 0;
}

static void A()
{
	double P, Q, R;
	get(P, Q, R);

	double ttl = P + Q + R;
	std::vector<double> p(3);
	p[0] = P / ttl;
	p[1] = Q / ttl;
	p[2] = R / ttl;

	std::sort(p.begin(), p.end());

	double ans = p[1] + p[2];
	printf("%.10lf\n", ans);
}