#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

int main() {
    int s = 0, p[3];
    for (int i = 0; i < 3; i++) {
        cin >> p[i];
        s += p[i];
    }

    double r = 0;
    for (int i = 0; i < 3; i++) {
        double t = (double)p[i] / s;
        r = max(r, max(t, 1 - t));
    }

    printf("%.12f\n", r);

    return 0;
}