#include <iostream>
using namespace std;
int main() {
	int S[6];
	for (int i = 0; i < 6; i++) {
		cin >> S[i];
	}
	int tmp = 0;
	for (int i = 0; i < 6; i++) {
		for (int j = i+1; j < 6; j++) {
			if (S[i] > S[j]) {
				tmp = S[i];
				S[i] = S[j];
				S[j] = tmp;
			}
		}
	}
	int Sum = 0;
	for (int i = 1; i < 5; i++) {
		Sum += S[i];
	}
	double AVG = (double)Sum / 4;
	printf("%.2f", AVG);
	return 0;
}