manba out

#include <bits/stdc++.h>
using namespace std;
int a,b,c,d,sum;
int main()
{
cin>>a>>b>>c>>d;
sum=a+b+c+d;
int maxx,minn;
maxx=max(max(max(a,b),c),d);
minn=min(min(min(a,b),c),d);
printf("%.2f",(sum-minn-maxx)/(2.00));
return 0;
}