#include<stdio.h>
int main()
{
	int i, s, sum = 0, max = -1, min = 1000;
	for (i = 0; i < 6; i++)
	{
		scanf("%d", &s);
		sum += s;
		if (s < min)min = s;
		if (s > max)max = s;
	}
	printf("%.2lf\n", (double)(sum - min - max) / 4);
	return 0;
}