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.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using static System.Console;

namespace ConsoleApp2
{
    class Program
    {
        static public long[] Sarray() { return ReadLine().Split().Select(long.Parse).ToArray(); }
        static public List<long> Slist() { return ReadLine().Split().Select(long.Parse).ToList(); }
        static void Main(string[] args)
        {
            var S = ReadLine();
            if (S[0] != 'A')
            {
                Console.WriteLine("WA");
                return;
            }
            if (S[1].ToString().ToLower() != S[1].ToString())
            {
                Console.WriteLine("WA");
                return;
            }
            if (S[S.Length-1].ToString().ToLower() != S[S.Length - 1].ToString())
            {
                Console.WriteLine("WA");
                return;
            }
            var cc = 0;
            for (var i=2;i< S.Length-1;i++)
            {
                if(S[i]=='C')
                {
                    cc++;
                    if(1<cc)
                    {
                        Console.WriteLine("WA");
                        return;
                    }
                }
                else
                {
                    if(S[i].ToString().ToLower()!= S[i].ToString())
                    {
                        Console.WriteLine("WA");
                        return;
                    }
                }
            }
            if (1 != cc)
            {
                Console.WriteLine("WA");
                return;
            }
            Console.WriteLine("AC");
        }

    }
}