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 (2.7.1) (judge verdict: Wrong Answer)

s=gets.chomp
flag=true
flag=false if !s[0]==?A
flag=false if s[2..s.size-2].count(?C)!=1
s.each_char.with_index do |si,idx|
  if si.upcase==si
    flag=false if idx==s.size-1||idx==1
    c=0
    if idx>2&&idx<s.size-1
      c+=1 if si==?C
    end
    flag=false if c>1
  end
end
puts flag ? 'AC':'WA'