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 C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;

int main() {
  string s; cin >> s;
  bool flag = true;
  int N = s.size();
  int c_count = 0;
  if(s[0]!='A'){
    flag = false;
  }else{
    for(int i=1;i<N;i++){
      if(s[i]=='C'){
        if(c_count>0){
          flag = false;
          break;
        }
        if(!(i>=2 && i<=N-2)){
          flag = false;
          break;
        }
        c_count += 1;
      } else{
        if(s[i]<'a' || s[i]>'z'){
          flag  = false;
          break;
        }
        
      }
    }
  }
  flag = (c_count==1);
  if(flag) cout << "AC" << endl;
  else cout << "WA" << endl;
}