#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007

using namespace std;


int main(void) {
	int s[7];
	int total = 0;
	double ave;
	int mini = 1000, maxi = -1;
	FOR(i, 1, 6) {
		cin >> s[i];
		total += s[i];
	}
	FOR(i, 1, 6) {
		mini = min(mini, s[i]);
		maxi = max(maxi, s[i]);
	}
	ave = (double)(total - mini - maxi) / (double)4;
	printf("%10.2lf\n", ave);
	return 0;
}