Online JudgeProblem SetAuthorsOnline ContestsUser
Web Board
Home Page
F.A.Qs
Statistical Charts
Problems
Submit Problem
Online Status
Prob.ID:
Register
Update your info
Authors ranklist
Current Contest
Past Contests
Scheduled Contests
Award Contest
User ID:
Password:
  Register
Language:
Smeech
Time Limit: 1000MSMemory Limit: 65536K
Total Submissions: 2746Accepted: 715

Description

Professor Octastichs has invented a new programming language, Smeech. An expression in Smeech may be a positive or negative integer, or may be of the form (p e1 e2) where p is a real number between 0 and 1 (inclusive) and e1 and e2 are Smeech expressions. The value represented by a Smeech expression is as follows:

  • An integer represents itself
  • With probability p, (p e1 e2) represents x + y where x is the value of e1 and y is the value of e2; otherwise it represents x - y.

Given a Smeech expression, what is its expected value?

Input

Input consists of several Smeech expressions, one per line, followed by a line containing ().

Output

For each expression, output its expected value to two decimal places.

Sample Input

7
(.5 3 9)
()

Sample Output

7.00
3.00

Source

[Submit]   [Go Back]   [Status]   [Discuss]

Home Page   Go Back  To top


All Rights Reserved 2003-2013 Ying Fuchen,Xu Pengcheng,Xie Di
Any problem, Please Contact Administrator