Problem:
Score : 200 points

Problem Statement

You are given a string S. Each character of S is uppercase or lowercase English letter.
Determine if S satisfies all of the following conditions:

The initial character of S is an uppercase A.

There is exactly one occurrence of C between the third character from the beginning and the second to last character (inclusive).

All letters except the A and C mentioned above are lowercase.

Constraints

4 ≤ |S| ≤ 10 (|S| is the length of the string S.)

Each character of S is uppercase or lowercase English letter.

Input

Input is given from Standard Input in the following format:

S

Output

If S satisfies all of the conditions in the problem statement, print AC; otherwise, print WA.

Sample Input 1

AtCoder

Sample Output 1

AC

The first letter is A, the third letter is C and the remaining letters are all lowercase, so all the conditions are satisfied.

Sample Input 2

ACoder

Sample Output 2

WA

The second letter should not be C.

Sample Input 3

AcycliC

Sample Output 3

WA

The last letter should not be C, either.

Sample Input 4

AtCoCo

Sample Output 4

WA

There should not be two or more occurrences of C.

Sample Input 5

Atcoder

Sample Output 5

WA

The number of C should not be zero, either.

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

import Control.Monad

data Judge = AC | WA deriving(Show)

alp :: [Char]
alp = ['A'..'Z']

solver' :: String -> Judge
solver' xs
    | (head xs) `elem` alp = WA
    | (last xs) `elem` alp = WA
    | otherwise            = 
        let ys = (init . tail) xs
            zs = filter (\z -> z `elem` alp) ys
            cs = length $ filter (\c -> c == 'C') zs
            in if cs /= 1 then WA 
               else if (length zs) > cs then WA 
               else AC


solver :: String -> Judge
solver []       = WA
solver (x:xs)
    | x == 'A'  = solver' xs
    | otherwise = WA


main :: IO ()
main = do
    line <- getLine
    print $ solver line