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 OCaml (4.02.3) (judge verdict: Accepted)

let list_of_str s = let rec f i = if i >= String.length s then [] else s.[i] :: f (i+1) in f 0
let () =
  Scanf.scanf "%s" (fun s ->
    s.[0] = 'A' &&
    1 = List.length (List.filter ((=) 'C') @@ list_of_str (String.sub s 2 (String.length s - 3))) &&
    2 = List.length (List.filter (fun x -> 'A' <= x && x <= 'Z') (list_of_str s))
  ) |> fun b -> print_endline @@ if b then "AC" else "WA"