//Normal

#define _GLIBCXX_DEBUG
#define ll long long
#include <bits/stdc++.h>
using namespace std;
using Graph = vector<vector<int>>;

void print(auto a){
  cout << a;
}

void prints(auto a){
  cout << a << " ";
}

void prints(){
  cout << " ";
}

void printl(auto a){
  cout << a << endl;
}

void printl(){
  cout << endl;
}

void fix(int n){
  cout << fixed << setprecision(n);
}

int main(){
  int sum = 0, maxv = 1e9*-1, minv = 1e9;
  int A;
  
  while(cin >> A){
    sum += A;
    maxv = max(maxv, A);
    minv = min(minv, A);
  }
  
  double ans = (double)(sum-maxv-minv)/4.0;
  
  fix(2);
  printl(ans);
  
  return 0;
}