#include <iostream>
#include<cstring>
#include<memory>

using namespace std;

bool isValid (string customerNumber) {
    if (customerNumber.length() != 6)
        return false;

    for(int i = 0; i < 2; i++)
    if (!isalpha(customerNumber[i]))
        return false;

   for (int i = 2; i < customerNumber.length(); i++)
       if(!isdigit(customerNumber[i]))
           return false;

   return true;
}

int main() {

    string cust_number = "AB1234";
    cout << isValid(cust_number);
  return 0;
}