#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

int main() {
    int p, q, r;
    cin >> p >> q >> r;
    double s = p+q+r;
    double a = p/s, b = q/s, c = r/s;
    printf("%.10lf\n", max({a, b, c, 1-a, 1-b, 1-c}));
    return 0;
}