#include <bits/stdc++.h>
using namespace std;
void NO() {
  cout << "NO\n";
  exit(0);
}
int a[100], freq[101];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    freq[a[i]]++;
  }
  int nice = 0, too_much = 0;
  for (int v = 1; v <= 100; v++) {
    if (freq[v] == 1) {
      nice ^= 1;
    } else if (freq[v] >= 3) {
      too_much = v;
    }
  }
  int split = -1;
  if (nice == 1) {
    if (too_much == 0) NO();
    split = too_much;
  }
  cout << "YES\n";
  char other = 'A';
  string ans(n, '*');
  for (int i = 0, id = 0; i < n; i++) {
    if (freq[a[i]] == 1) {
      ans[i] = ('A' + id);
      id ^= 1;
    } else if (a[i] == split) {
      ans[i] = ('A' + id);
      id ^= 1;
      other = 'A' + id;
      split = 0;
    }
  }
  for (char& ch : ans)
    if (ch == '*') ch = other;
  cout << ans << endl;
  return 0;
}
