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: Accepted)

#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i, s, e) for (int(i) = (s); (i) <= (e); (i)++)
#define all(x) x.begin(), x.end()

int main(){
  string s;
  cin >> s;
  string t = s.substr(2,s.size() - 2);
  t = t.substr(0,t.size() - 1);
  bool OK = true;
  int A = 1;
  int C = 1;
  for(char c : s){
    if('a' <= c && c <= 'z'){

    }
    else if(c == 'A'){
      A--;
    }
    else if(c == 'C'){
      C--;
    }
    else{
      cout << "WA" << endl;
      return 0;
    }
  }
  if(s[0] == 'A' && t.find('C') != t.npos && A == 0 && C == 0){
    cout << "AC" << endl;
  }
  else{
    cout << "WA" << endl;
  }
}