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: Wrong Answer)

string = gets.chomp.split("")
answer = "AC"

if string.first == "A" && string.last != "C" && string.last != "A"
  string = string.slice(2...string.length-1)
  cnt = 0
  idx = []

  string.each_with_index do |s, index|
    if s == "C"
      cnt += 1
      idx.push(index)
    end
  end
  
  if cnt == 1 && !idx.empty?
    string.delete_at(idx.first)
    new_string = []
    string.each_with_index do |s, index|
      new_string[index] = s.downcase
    end

    answer = "WA" unless string == new_string
  else
    answer = "WA"
  end
else
  answer = "WA"
end

puts answer