#include <bits/stdc++.h>
using namespace std;
int c[100];
map<int, int> mp;
int main() {
  int i, n;
  int arr[100];
  int m = 0;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> arr[i];
    mp[arr[i]]++;
  }
  m = 1;
  for (i = 0; i < n; i++) {
    if (mp[arr[i]] == 1) {
      if (m)
        c[i] = 1;
      else
        c[i] = 2;
      m = 1 - m;
    }
  }
  i = 0;
  if (m == 0) {
    for (i = 0; i < n; i++) {
      if (!c[i] && mp[arr[i]] > 2) {
        c[i] = 2;
        break;
      }
    }
  }
  if (i == n) {
    cout << "NO" << endl;
    return 0;
  } else {
    cout << "YES" << endl;
    for (int i = 0; i < n; i++) {
      if (c[i] == 2)
        cout << "B";
      else
        cout << "A";
    }
    cout << endl;
  }
  return 0;
}
