#include<bits/stdc++.h>

using namespace std;
using ll = long long;
inline int ri() { int n; cin >> n; return n;}
const int INF = 1e9;

int main()
{
	int r = ri(), p = ri(), q = ri();
	int nax = max({r, p, q}), mid = r + p + q - nax - min({r, p, q});
	cout << fixed <<setprecision(12) << (double)(nax + mid) / (r + p + q) << endl; 
}