#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

int main(void) {
	double s[6], sum = 0, max = 0, min = 100;
	int or , sr;

	for (int i = 0; i < 6; i++)
		scanf("%lf", &s[i]);

	for (int j = 0; j < 6; j++) {
		if (max <= s[j]) {
			max = s[j];
			or = j;
		}
		if (min >= s[j]) {
			min = s[j];
			sr = j;
		}
	}

	if (or == sr)
		printf("%.2lf\n", max);
	else {
		s[or ] = -1;
		s[sr] = -1;

		for (int k = 0; k < 6; k++) {
			if (s[k] >= 0)
				sum += s[k];
		}
		printf("%.2lf\n", sum / 4.0);
	}

	return 0;
}