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;
using System.Linq;
using System.Collections.Generic;
class Program
{
    static void Main(string[] args)
    {
        string s = Console.ReadLine();
        if(s[0] != 'A')
        {
            Console.WriteLine("WA");
            return;
        }
        int Cpos = -1;
        int CCount = 0;
        for(int i = 2; i < s.Length - 2; i++)
        {
            if (s[i] == 'C')
            {
                Cpos = i;
                CCount++;
            }
        }
        if(Cpos == -1 || CCount != 1)
        {
            Console.WriteLine("WA");
            return;
        }
        for(int i = 1; i < s.Length; i++)
        {
            if(i != Cpos && s[i] - 'A' <= 26)
            {
                Console.WriteLine("WA");
                return;
            }
        }
        Console.WriteLine("AC");
    }
}