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: Wrong Answer)

use std::io;

fn main() {
    let mut S = String::new();
    let mut f = false;
    io::stdin().read_line(&mut S).expect("ss");

    for (i, c) in S.chars().enumerate() {
        if i==0 && c!='A' {
            println!("WA");
            return ;
        }
        if i>0 && c!='C' && c.is_uppercase() {
            println!("WA");
            return ;
        }
        if i>1 && i<S.len() && c=='C' {
            f = true;
        }
        if i>2 && f && c=='C' {
            println!("WA");
            return;
        }
        if i==S.len()-1 && !f {
            println!("WA");
            return;
        }
    }
    println!("AC");
}