#include <bits/stdc++.h>
using namespace std;
int n;
string s;
int cnt[102];
int a[102];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n;
  for (int i = 0; i <= 100; i++) cnt[i] = 0;
  for (int i = 0; i <= n - 1; i++) {
    cin >> a[i];
    cnt[a[i]]++;
  }
  int good = 0;
  vector<int> v1, v2;
  for (int i = 0; i <= 100; i++)
    if (cnt[i] == 1) {
      good++;
      v1.push_back(i);
    }
  int semigood = 0;
  for (int i = 0; i <= 100; i++)
    if (cnt[i] > 2) {
      semigood++;
      v2.push_back(i);
    }
  bool ok[102];
  for (int i = 0; i <= 100; i++) ok[i] = false;
  if (!(good & 1)) {
    vector<int> ms1, ms2;
    int sz = (int)v1.size();
    for (int i = 0; i <= sz - 1; i++) ok[v1[i]] = true;
    bool chk = true;
    cout << "YES\n";
    for (int i = 0; i <= n - 1; i++) {
      if (ok[a[i]] && chk) {
        cout << "A";
        chk = false;
      } else if (ok[a[i]] && !chk) {
        cout << "B";
        chk = true;
      } else
        cout << "A";
    }
    cout << "\n";
  } else {
    if (semigood) {
      cout << "YES\n";
      int sz = (int)v1.size();
      for (int i = 0; i <= sz - 1; i++) ok[v1[i]] = true;
      bool chk = true, done = true;
      for (int i = 0; i <= n - 1; i++) {
        if (ok[a[i]] && chk) {
          cout << "A";
          chk = false;
        } else if (ok[a[i]] && !chk) {
          cout << "B";
          chk = true;
        } else if (a[i] == v2[0] && done) {
          cout << "B";
          done = false;
        } else
          cout << "A";
      }
    } else
      cout << "NO\n";
  }
  return 0;
}
