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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;

public class Hello
{
    public static void Main()
    {
        var s = Console.ReadLine().Trim();
        Console.WriteLine(check(s) ? "AC":"WA");
    }
    public static bool check (string s)
    {
        var sL = s.Length;
        if (s[0] != 'A') return false;
        var s2 = s.Substring(2, sL - 3);
        var a = s2.Length - s2.Replace("C", "").Length;
        if (a != 1) return false;
        var w = s2.Replace("C", "c");
        for (int i = 1; i < w.Length; i++)
            if (Char.IsUpper(w[i])) return false;
        return true;
    }
}