n=int(input())
scorse=list(map(float,input().split(',')))
scorse.sort()
vivid=scorse[2:-2]
avg=sum(vivid)/(n-4)
print(f"{avg:.2f}")
bj1pbnQoaW5wdXQoKSkKc2NvcnNlPWxpc3QobWFwKGZsb2F0LGlucHV0KCkuc3BsaXQoJywnKSkpCnNjb3JzZS5zb3J0KCkKdml2aWQ9c2NvcnNlWzI6LTJdCmF2Zz1zdW0odml2aWQpLyhuLTQpCnByaW50KGYie2F2ZzouMmZ9Iik=