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.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String S = sc.next();

		boolean startsFromA = (S.charAt(0) == 'A');
		String seekC = S.substring(2, S.length() - 1);
		int indexOfC = seekC.indexOf('C');
		boolean containsSingleC = (indexOfC != -1 && seekC.indexOf('C', indexOfC + 1) == -1);
		boolean lowersOtherThanAC = isLowersOtherThanAC(S, indexOfC + 2);
		System.out.println((startsFromA && containsSingleC && lowersOtherThanAC) ? "AC" : "WA");
	}

	private static boolean isLowersOtherThanAC(String S, int indexOfC) {
		char[] array = S.toCharArray();
		int length = array.length;
		for (int i = 1; i < length; i++) {
			if (i != indexOfC && Character.isUpperCase(array[i])) {
				return false;
			}
		}
		return true;
	}
}