#include <bits/stdc++.h>
using namespace std;
int n;
int count_input[101] = {0};
int input[101] = {0};
int countOnce = 0, countTwice = 0;
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> input[i];
    count_input[input[i]]++;
  }
  for (int i = 1; i <= 101; i++) {
    if (count_input[i] == 1)
      countOnce++;
    else if (count_input[i] == 2)
      countTwice++;
  }
  if (countOnce % 2 == 0) {
    cout << "YES" << endl;
    int A = 0;
    for (int i = 1; i <= n; i++) {
      if (count_input[input[i]] == 1) {
        if (A < countOnce / 2) {
          cout << 'A';
          A++;
        } else
          cout << 'B';
      } else {
        cout << 'A';
      }
    }
    cout << endl;
  } else {
    if (countOnce + countTwice * 2 == n) {
      cout << "NO" << endl;
    } else {
      cout << "YES" << endl;
      int A = 0;
      bool bA = true;
      for (int i = 1; i <= n; i++) {
        if (count_input[input[i]] == 1) {
          if (A < countOnce / 2) {
            cout << 'A';
            A++;
          } else
            cout << 'B';
        } else if (count_input[input[i]] == 2) {
          cout << 'A';
        } else {
          if (bA) {
            cout << 'A';
            bA = false;
          } else
            cout << 'B';
        }
      }
      cout << endl;
    }
  }
  return 0;
}
