#include<iostream>
#include<algorithm>
using namespace std;

int main() {
	double a[6],s=0;
	for (int i = 0;i < 6;i++)cin >> a[i],s+=a[i];
	sort(a, a + 6);
	printf("%.2f\n",(s - a[0] - a[5]) / 4.0);
}