#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int arr[n], brr[101] = {0}, k = 0, crr[100] = {0}, drr[100] = {0}, k1 = 0;
  for (int i = 0; i < n; i++) {
    cin >> arr[i];
    brr[arr[i]]++;
  }
  for (int i = 0; i <= 100; i++) {
    if (brr[i] == 1) {
      crr[k] = i;
      k++;
    }
    if (brr[i] > 2) {
      drr[k1] = i;
      k1++;
    }
  }
  int kcopy = k;
  if (k % 2 == 0) {
    cout << "YES\n";
    int x = 0;
    for (int i = 0; i < n; i++) {
      int check = 0;
      if (brr[arr[i]] == 1) {
        x++;
        if (x <= kcopy / 2) {
          cout << "A";
        } else
          cout << "B";
      } else
        cout << "B";
    }
  } else if (k1 >= 1) {
    cout << "YES\n";
    int y = 0, stop = 0;
    for (int i = 0; i < n; i++) {
      if (brr[arr[i]] == 1) {
        y++;
        if (y <= kcopy / 2) {
          cout << "A";
        } else
          cout << "B";
      } else if (brr[arr[i]] > 2 && stop != 1) {
        cout << "A";
        stop = 1;
      } else
        cout << "B";
    }
  } else
    cout << "NO";
}
