#include <iostream>
#include <stdio.h>
#include <math.h>
#include <vector>
#include <algorithm>
using namespace std;

int main(){
	vector<int> s(6);
	cin >> s[0] >> s[1] >> s[2] >> s[3] >> s[4] >> s[5] ;
	int mx=-1000,mn=1000;

	sort(s.begin(),s.end());

	double ans=0.0;
	for(int i=1;i<5;i++){
		ans += s[i];
	}
	ans /= 4;

	printf("%.2lf",ans);
}