Distorted Palindrome

Problem code: ENCD12

All submissions for this problem are available.

A palindrome is a string of letters that is equal to itself when reversed. Given an input string, not necessarily a palindrome, compute the number of times you need to swap to transform the string into a palindrome. By swap we mean reversing the order of two adjacent symbols. For example, the string "mamad" may be transformed into the palindrome "madam" with 3 swaps:
swap "ad" to get "mamda"
swap "md" to get "madma"
swap "ma" to get "madam"

Input

The Input will have number of test cases. For each test case, one line of input containing a string of up to 100 lowercase letters will be there. Terminate the input with a 0(zero).

Output

Output consists of one line. This line will contain the number of swaps, or "Impossible" if it is not possible to transform the input string to a palindrome.

Example

Input:
mamad
asflkj
aabb
0
Output:
3
Impossible
2

Author: rscrbv
Date Added: 20-01-2010
Time Limit: 3 sec
Source Limit: 50000 Bytes
Languages: ADA, ASM, BASH, BF, C, C99 strict, CAML, CLOJ, CLPS, CPP 4.0.0-8, CPP 4.3.2, CS2, D, ERL, F#, FORT, GO, HASK, ICK, ICON, JAR, JAVA, JS, LISP clisp, LISP sbcl, LUA, NEM, NICE, PAS fpc, PAS gpc, PERL, PERL6, PHP, PIKE, PRLG, PYTH, PYTH 3.1.2, RUBY, SCALA, SCM guile, SCM qobi, ST, TEXT, WSPC


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