#include<iostream>
#include<vector>
#include<algorithm>
#include <iomanip>
#define NUM 6

using namespace std;

int main()
{
    vector<int> v;
    int n;
    for(int i=0; i<NUM; i++) {
        cin>>n;
        v.push_back(n);
    }
    
    sort(v.begin(),v.end());
    
    double score=0.0;
    for(int i=1; i<NUM-1; i++) {score+=v[i];}
    printf("%.2f\n",score/4.00);
    return 0;
}