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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
)

func main() {
	var S string
	fmt.Scan(&S)

	if S[0] != 'A' {
		fmt.Println("WA")
		return
	}

	num := 0
	pos := 0
	for i := 2; i < len(S)-1; i++ {
		if S[i] == 'C' {
			num++
			pos = i
		}
	}
	if num != 1 {
		fmt.Println("WA")
		return
	}

	for i := 1; i < len(S); i++ {
		if pos == i {
			continue
		}
		if S[i] < 'a' || 'z' < S[i] {
			fmt.Println("WA")
			return
		}
	}

	fmt.Println("AC")
}