#include <bits/stdc++.h> //#include <chrono> //#pragma GCC optimize("Ofast") using namespace std; #define reps(i,s,n) for(int i = s; i < n; i++) #define rep(i,n) reps(i,0,n) #define Rreps(i,n,e) for(int i = n - 1; i >= e; --i) #define Rrep(i,n) Rreps(i,n,0) #define ALL(a) a.begin(), a.end() #define fi first #define se second typedef long long ll; typedef vector<ll> vec; typedef vector<vec> mat; ll N,M,H,W,Q,K,A,B; string S; typedef pair<ll, ll> P; const ll INF = (1LL<<60); int main() { vector<double> a(3); rep(i, 3) cin>>a[i]; cout<<fixed<<setprecision(10)<<1.0 - *min_element(ALL(a)) / accumulate(ALL(a), 0.0)<<endl; }