var inpt = readLine()!.split(separator: " ").map{ Int($0)! * 100 }.sorted()
inpt.remove(at: 0)
inpt.remove(at: inpt.count-1)
var ans = String(inpt.reduce(0, { $0 + $1 }) / inpt.count)
ans = ans.prefix(ans.count-2) + "." + ans.suffix(2)
print(ans)