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.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace abc104b
{
    class Program
    {
        static void Main(string[] args)
        {
            var s = Console.ReadLine();
            if (satisfyCondition1(s) && satisfyCondition2(s) && satisfyCondition3(s))
                Console.WriteLine("AC");
            else
                Console.WriteLine("WA");
        }
        static bool satisfyCondition1(string s)
        {
            return s.StartsWith("A");
        }
        static bool satisfyCondition2(string s)
        {
            var t = s.Substring(2, s.Length - 3);
            return t.Count(x => x == 'C') == 1 ? true : false;
        }
        static bool satisfyCondition3(string s)
        {
            var posC = s.IndexOf('C');
            var t1 = s.Substring(1, posC - 2);
            var t2 = s.Substring(posC + 1, s.Length - (posC + 1));
            return t1.Count(x => 'A' <= x && x <= 'Z') == 0 && t2.Count(y => 'A' <= y && y <= 'Z') == 0;
        }
    }
}