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 (
	"bufio"
	"fmt"
	"os"
	"strings"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	var str string
	scanner.Scan()
	fmt.Sscanf(scanner.Text(), "%s", &str)
	chars := strings.Split(str, "")

	ans := true
	cond2 := false
	for i := 0; i < len(chars); i++ {
		if i == 0 {
			if chars[i] != "A" {
				ans = false
				break
			}
			continue
		}
		if 2 <= i && i <= len(chars)-2 {
			if chars[i] == "C" && !cond2 {
				cond2 = true
				continue
			} else if chars[i] == "C" && cond2 {
				ans = false
				break
			}
		}
		if strings.ToLower(chars[i]) != chars[i] {
			ans = false
			break
		}
	}

	if ans && cond2 {
		fmt.Println("AC")
	} else {
		fmt.Println("WA")
	}
}