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 solve(s) {
    fmt.Println("AC")
  } else {
    fmt.Println("WA")
  }
}
func solve(s string) bool{
  var c byte
  var i,n int
  n = len(s)
  f := false
  for i = 0; i <  n; i++ {
    c = s[i]
    if i == 0 && c != 'A' {
      return false;
    }
    if c == 'C' {
      if 2 <= i && i < n-1  {
        if f {
          return false;
        }
        f = true
      } else {
        return false;
      }
    } else if 'A' < c && c <= 'Z'{
      return false;
    }
  }
  return f;
}