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;

namespace AcCepted
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = Console.ReadLine();
            bool result = false;

            if (s.StartsWith("A"))
            {
                string tmpS = s.Remove(0, 2);
                tmpS = tmpS.Remove(tmpS.Length - 1, 1);
                int cPos = s.IndexOf('C');

                if (tmpS.Count(a => a == 'C') == 1)
                {
                    string upper = s.Remove(cPos, 1);
                    upper = upper.Remove(0, 1);
                    
                    if (IsUpper(upper))
                    {
                        result = true;
                    }
                }
            }

            Console.WriteLine(result ? "AC" : "WA");
        }

        private static bool IsUpper(string str)
        {
            bool result = true;

            foreach (char c in str)
            {
                if (char.IsUpper(c))
                {
                    result = false;
                }
            }

            return result;
        }
    }
}