#include<iostream>
#include<cstdio>
#include<string>
using namespace std;

int main() {
	int max = -1, min = 101, s;
	
	int sum = 0;
	for (int i = 0; i < 6; i++)
	{
		scanf("%d", &s);
		sum += s;
		if (max < s) max = s;
		if (min > s) min = s;
	}

	float ans = (float)(sum - max - min) / (float)4;
	printf("%.2f\n", ans);

	return 0;
}