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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;
public class Main {

  public static void main(String[] args) { 
      Scanner sc = new Scanner(System.in);
      String s = sc.next();
      if(s.charAt(0) != 'A') {
        System.out.println("WA");
        return;
      }

      String subS = s.substring(Math.min(2, s.length()-1), Math.max(2, s.length()-1));
      int cnt = 0;
      int idx = -1;
      for(int i = 0; i < subS.length(); i++) {
        if(subS.charAt(i) == 'C') {
          cnt++;
          idx = i + 2;
        }
      }
      if(cnt != 1) {
        System.out.println("WA");
        return;
      }
      for(int i = 1; i < s.length(); i++) {
        if(i == idx) continue;
        if(!Character.isLowerCase(s.charAt(i))){
          System.out.println("WA");
          return;
        }
      }

      System.out.println("AC");
  }
}