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
北京大学《ACM-ICPC竞赛训练》暑期课面向全球招生。容量有限,报名从速!
Language:
Word Rings
Time Limit: 7000MSMemory Limit: 65536K
Total Submissions: 7839Accepted: 1749Special Judge

Description

A word ring is a sequence of words where the last two letters of each word are the same as the first two letters of the next word (and the last two letters of the last word are the same as the first two letters of the first word). For example, the following sequence is a word ring:

intercommunicational
alkylbenzenesulfonate
tetraiodophenolphthalein

Your task is to write a program that, given a list of words, finds a word ring. You have to make the word ring as impressive as possible: the average length of the words in the ring has to be as large as possible. In the above example, the average length is (20 + 21 + 24)/3 ≈ 21.6666 , which makes it somewhat impressive. Note that each word can be used at most once in the ring, and the ring can consist of a single word.

Input

The input contains several blocks of test cases. Each case begins with a line containing a single integer 1 ≤ n ≤ 100000 , the number of possible words that can be used. The next n lines contain these words. The words contain only the characters `a'-`z' and the length of each word is at most 1000.

The input is terminated by a block with n = 0 .

Output

For each test case in the input, you have to output a single number on a separate line: the maximum average length of a ring composed from (a subset of) the words given in the input. The average length should be presented as a real number with two digits of precision. If it is not possible to compose a ring from these words, then output `No solution.' (without quotes). To avoid rounding problems, we accept solutions with a maximum of ±0.01 error.

Sample Input

3
intercommunicational
alkylbenzenesulfonate
tetraiodophenolphthalein
0

Sample Output

21.66

Hint

Huge input file, 'scanf' recommended to avoid TLE.

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