#include <iostream>
#include <cstdio>
#include <vector>
#include <cmath>
#include <cstring>
#include <numeric>
#include <algorithm>
#include <functional>
#include <array>
#include <map>
using namespace std;

#define Getsign(n) ((n > 0) - (n < 0))

typedef vector<int> Ivec;
typedef pair<int, int> Pos;

int main() {
	int point[6], sum = 0;
	int Max = 0, Min = 100, maxnum, minnum;
	for (int i = 0; 6 > i; i++) {
		scanf("%d", &point[i]);
		if (Max <= point[i]) {
			Max = point[i];
			maxnum = i;
		}
		if (Min >= point[i]) {
			Min = point[i];
			minnum = i;
		}
		sum += point[i];
	}
	printf("%.2f\n", (double)(sum-Max-Min)/4);
	return 0;
}