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.Linq;
using System.Collections.Generic;

namespace _0030
{
    
    class Program
    {

        
        static void Main(string[] args)
        {
            string str = Console.ReadLine();

            //4文字以上が前提
            if(str.Length < 4)
            {
                Console.WriteLine("WA");
                return;
            }

            //1文字目はA
            if(str[0] != 'A')
            {
                Console.WriteLine("WA");
                return;
            }

            //2文字目は小文字
            if (char.IsUpper(str[1]))
            {
                Console.WriteLine("WA");
                return;
            }
           
            int ccnt = 0;  //Cの入っている数のカウント

            //Cが入っている区間
            for(int i = 2; i < str.Length - 1; i++)
            {
                if(str[i] == 'C')
                {                    
                    ccnt++;
                }
                else
                {
                    //C以外の大文字がでたらWA
                    if (char.IsUpper(str[i]))
                    {
                        Console.WriteLine("WA");
                        return;
                    }
                }               
                
            }

            //Cが2つ以上出てたらWA
            if (ccnt != 1)
            {
                Console.WriteLine("WA");
                return;
            }

            //最後の1文字は小文字
            if (char.IsUpper(str[str.Length - 1]))
            {
                Console.WriteLine("WA");
                return;
            }
            else
            {
                Console.WriteLine("AC");
            }        
       
        }
    }
}