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 Scala (2.11.7) (judge verdict: Runtime Error)

import scala.io.StdIn._
object Main{
  def main(args: Array[String]): Unit ={
    val s = readLine
    val s1 = s.substring(2,s.length-3)
    val b1 = s.startsWith("A")
    val b2 = s1.matches("[^C]*C[^C]*")
    val index = s1.indexOf("C") + 2 
    val s2 = new StringBuilder(s.substring(1)).replace(index - 1 ,index  ,"").toString
    val b3 = s2.toLowerCase() == s2
    if(b1&&b2&&b3)
      println("AC")
    else
      println("WA")
  }
}