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 <iostream>
#include <iomanip>
#include <algorithm>
using namespace std;
#include <cstdio>
#include <tuple>
#include <string>
#include <vector> 
#include <set>
#include <string.h>
#include <map>
#include <cmath>
#include <deque>
using ll = long long;
using Graph = vector<vector<int>>;
#include <queue>
#include <stack>
const int MAX = 3;
int main(){
    int a = 0;
    int c = 0;
    string s;
    cin >> s;
    bool f = true;
    for(int i=0;i < s.length();i++){
        if(s[0] == 'A'){
            //区間にCがあるか
            if(i >= 2 && i <= s.length()-3 && s[i] == 'C'){
                if(c != 0){
                    f = false;
                    break;
                }
                c=1;
            }
            //区間外にCがあるか
            if(!(i >= 2 && i <= s.length()-3) && (s[i] == 'C')){
                
                f = false;
                break;
                
            }
            //大文字小文字
            if(i >= 1 && (s[i] < 'a' || s[i] > 'z') && s[i] != 'C'){
                f = false;
                break;
            }
        }else{
            f = false;
            break;
        }
    }
    if(c != 1) f = false;

    if(f) cout << "AC" << endl;
    else cout << "WA" << endl;
    return 0;
}