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