#include<stdio.h>
int main()
{
int n,x;
scanf("%d",&n);
int i=1,max=0,min=100000;
double sum=0,avg;
for(i=1;i<n;i++)
{
scanf("%d",&x);
if(x>max)
max=x;
if(x<min)
min=x;
sum=sum+x;
}
avg=sum/(n-2);
printf("%.2lf",avg);
}