#include<bits/stdc++.h>
using namespace std;
int main(){
  long double A,B,C;
  cin>>A>>B>>C;
  long double D=A/(A+B+C),E=B/(A+B+C),F=C/(A+B+C);
  cout<<fixed<<setprecision(16)<<max({D,E,F,D+E,E+F,F+D})<<endl;
}