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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
class Program
{
    static void Main(string[] args)
    {
            // 入力
            string sS = Console.ReadLine().Trim();

            // 解析
            string sOut = "AC";
            string sTmp = sS.Substring(2, sS.Length - 3);
            string sTm2 = sTmp.Replace("C", "");
            if (sS.Substring(0, 1) == "A")
            {
                if (sTmp.Length - 1 == sTm2.Length)
                {
                    sTm2 = sS.Substring(1, 1) + sTm2 + sS.Substring(sS.Length - 1, 1);
                    for (int i = 0; i < sTm2.Length; i++)
                    { if (char.IsUpper(sTm2, i)) { sOut = "WA"; break; } }
                }
                else
                { sOut = "WA"; }
            }
            else
            { sOut = "WA"; }

            //出力
            Console.WriteLine("{0}", sOut.ToString());

#if DEBUG
        Console.WriteLine("続行するには何かキーを押してください．．．");
        Console.ReadKey();
#endif

    }

}