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;

class Program
{
    static void Main()
    {
        string s = Console.ReadLine();
        int pos = 0;
        bool flag = false;

        for (int i = 2; i < s.Length - 1; i++)
        {
            if (s[i] == 'C' && flag == true)
            {
                flag = false;
                break;
            }
            if (s[i] == 'C')
            {
                flag = true;
                pos = i;
            }
        }

        if (s[0] == 'A' && flag == true) flag = true;

        if (flag)
        {
            for (int i = 1; i < s.Length; i++)
            {
                if (char.IsUpper(s[i]) == true && i != pos)
                {
                    flag = false;
                    break;
                }
            }
        }

        if (flag)
            Console.WriteLine("AC");
        else
            Console.WriteLine("WA");
    }
}