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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
$s=trim(fgets(STDIN));
$n=strlen($s);
if($s[0]=="A"){
$c=1;
$i=1;
while($i<$n){
if($c==1&&$i>1&&$i<$n-1){
if($s[$i]=="C"){
--$c;
}else{
if($s[$i]!=strtolower($s[$i])){
echo "WA";
exit;
}
}
}else{
if($s[$i]!=strtolower($s[$i])){
echo "WA";
exit;
}
}
++$i;
}
echo ($c==0)?"AC":"WA";
}else{
echo "WA";
}