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 Ruby (2.3.3) (judge verdict: Accepted)

s = gets.chomp
ans = 'AC'
count = 0

s.length.times do |i|
  if s[0] != 'A'
    ans = 'WA'
  end

  if i > 0
    unless s[i] > s[i].upcase
      if s[i] == 'C' && i > 1
        count += 1
        if count == 2
          ans = 'WA'
        end
        if s.length-1 == i
          ans = 'WA'
        end
      else
        ans = 'WA'
      end
    end
  end
end

if count == 0
  ans = 'WA'
end

puts ans