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 Common Lisp (SBCL 1.1.14) (judge verdict: Accepted)

(defun upcase-less-string-p (str)
  (labels ((capital-p (chr)
             (equal (char-upcase chr) chr)))
    (if (characterp str)
        (if (capital-p str)
            nil
            t)
        (if (capital-p (char str 0))
            nil
            (upcase-less-string-p (subseq str 1))))))

(let ((s (coerce (read-line) 'list)))
  (if (and (equal (car s) #\A)
           (equal (count #\C s) 1)
           (< 1 (position #\C s))
           (< (position #\C s) (1- (length s)))
           (eval (cons 'and
                       (mapcar #'upcase-less-string-p
                               (append (subseq s 1 (position #\C s))
                                       (subseq s (1+ (position #\C s))))))))
      (princ "AC")
      (princ "WA")))