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 Rust (1.15.1) (judge verdict: Accepted)

fn main() {
    let mut input = String::new();
    std::io::stdin().read_line(&mut input).unwrap();

    let mut input: Vec<_> = input.trim().chars().collect();


    if input[0] != 'A' {
        println!("WA");
        return;
    } else {
        input.remove(0);
    }

    if input[1..input.len()-1].iter().filter(|&&c| c == 'C').count() != 1 {
        println!("WA");
        return;
    } else {
        let pos = input[1..input.len()-1].iter().position(|&c| c == 'C').unwrap() + 1;
        input.remove(pos);
    }

    if input.iter().filter(|c| c.is_uppercase()).count() != 0 {
        println!("WA");
        return;
    }

    println!("AC");
}