#include<iostream>
#include<cstdio>
#include<vector>
#include<map>
#include<string>
#include<sstream>
#include<cmath>
#include<climits>
#include<algorithm>
#include<bitset>
#include<set>
#include<stack>
#include<queue>
#include<iomanip>
#include<memory.h>
using namespace std;  
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
#define rep(i,n) for(ll i=0;i<(n);i++)  
#define pb push_back  
#define ALL(a) (a).begin(),(a).end()
#define FST first
#define SEC second  
const int INF = (INT_MAX/2);
const ll LLINF = (LLONG_MAX/2);
const double eps = 1e-5;
const double PI = M_PI;  
#define DEB cerr<<"!"<<endl
#define SHOW(a,b) cerr<<(a)<<" "<<(b)<<endl
#define SHOWARRAY(ar,i,j) REP(a,i)REP(b,j)cerr<<ar[a][b]<<((b==j-1)?((a==i-1)?("\n\n"):("\n")):(" "))
#define DIV int(1e9+7)
inline ll pow(ll x,ll n,ll m){ll r=1;while(n>0){if((n&1)==1)r=r*x%m;x=x*x%m;n>>=1;}return r%m;}
 
int main(){
  double score[6];
  rep(i,6) cin >> score[i];
  double ma = 0;
  double mi = 1000;
  double sum = 0;
  rep(i,6){
    sum += score[i];
    ma =max(ma,score[i]);
    mi =min(mi,score[i]);
  }
  
  cout << fixed << setprecision(2) << (sum-mi-ma)/4.0 << endl;
  
  return 0;
}