#include <bits/stdc++.h>
using namespace std;
int ct[101];
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0);
  int n;
  cin >> n;
  int s[n];
  for (int i = 0; i < n; i++) {
    cin >> s[i];
    ct[s[i]]++;
  }
  int ct1 = 0;
  for (int i = 0; i < 101; i++) {
    if (ct[i] == 1) ct1++;
  }
  bool f = 0;
  int c1 = 0, c2 = 0;
  string ans = "";
  if (ct1 % 2 == 0) {
    cout << "YES\n";
    for (int i = 0; i < n; i++) {
      if (ct[s[i]] == 1) {
        if (f) {
          ans += 'A';
          f = 1 - f;
        } else {
          f = 1 - f;
          ans += 'B';
        }
      } else {
        ans += 'A';
      }
    }
    cout << ans;
  } else {
    bool f = 0;
    for (int i = 0; i < n; i++) {
      if (ct[s[i]] == 1) {
        if (f) {
          ans += 'A';
          f = 1 - f;
          c1++;
        } else {
          f = 1 - f;
          ans += 'B';
          c2++;
        }
      } else {
        ans += 'A';
      }
    }
    for (int i = 0; i < n; i++) {
      if (ct[s[i]] > 2) {
        for (int j = i + 1; j < n; j++) {
          if (s[j] == s[i]) ans[j] = 'B';
        }
        c1++;
        break;
      }
    }
    if (c1 == c2) {
      cout << "YES\n";
      cout << ans;
    } else
      cout << "NO";
  }
  return 0;
}
