#include <bits/stdc++.h>
using namespace std;
using ll        = long long;
using ld        = long double;
using vl        = vector<ll>;
using vd        = vector<ld>;
using vs        = vector<string>;
using vb        = vector<bool>;
using vvl       = vector<vector<ll>>;
using vvd       = vector<vector<ld>>;
using vvs       = vector<vector<string>>;
using vvb       = vector<vector<bool>>;
using pll       = pair<ll, ll>;
constexpr ll mod= 1e9 + 7;
#define ALL(x) (x).begin(), (x).end()
#define REP(i, n) for(ll(i)= 0; (i) < (n); (i)++)
#define REPS(i, n) for(ll(i)= 1; (i) <= (n); (i)++)
#define RREP(i, n) for(ll(i)= (n - 1); (i) >= 0; (i)--)
#define RREPS(i, n) for(ll(i)= (n); (i) > 0; (i)--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
#define YES(n) ((n) ? "YES" : "NO")
#define Yes(n) ((n) ? "Yes" : "No")
#define yes(n) ((n) ? "yes" : "no")

template <class T>
inline void chmin(T& a, T b) {
    if(a > b) { a= b; }
}

template <class T>
inline void chmax(T& a, T b) {
    if(a < b) { a= b; }
}

signed main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);
    vl P(3);
    REP(i,3)cin >> P[i];
    sort(ALL(P),greater<>());
    ll sum = P[0] + P[1] + P[2];
    if(sum - P[2] >= P[0]){
        cout << (ld)(sum - P[2])/(ld)sum << "\n";
    }else{
        cout << (ld)(P[0])/(ld)sum << "\n";
    }
}