#include <cstdio>
using namespace std;
int main(void){
	int s,i,min=100,max=0,sum=0;
	for(i=0;i<6;i++){
		scanf("%d",&s);
		if(s>=max) max=s;
		if(s<=min) min=s;
		sum+=s;
	}
	printf("%6.2lf",((double)(sum-(min+max)))/4 );
}