#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;
typedef long long int ll;

int main(){
	int a,b,c,d,e,f; cin >>a>>b>>c>>d>>e>>f;
	int sum=a+b+c+d+e+f-max(max(max(a,b),max(c,d)),max(e,f))-min(min(min(a,b),min(c,d)),min(e,f));
	printf("%.2f\n",(double)sum/4);
}