#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target(sse, sse2, sse3, ssse3, sse4, popcnt, tune = native)
using namespace std;
const int inf = 1e18 + 239;
signed main() {
  int n;
  cin >> n;
  vector<int> a(n), cnt(101, 0);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    cnt[a[i]]++;
  }
  vector<int> uniq, nuq;
  for (int i = 0; i < int(cnt.size()); i++) {
    if (cnt[i] == 1) uniq.push_back(i);
    if (cnt[i] > 2) nuq.push_back(i);
  }
  if (int(uniq.size()) % 2 == 1 && int(nuq.size()) == 0) {
    cout << "NO"
         << "\n";
    return 0;
  }
  vector<int> color(101, -1);
  for (int i = 0; i < int(uniq.size()); i++) {
    color[uniq[i]] = (i % 2);
  }
  int paint = -2;
  if (int(uniq.size()) % 2 == 1) {
    paint = nuq[0];
  }
  for (int i = 0; i < nuq.size(); i++) {
    color[nuq[i]] = 0;
  }
  string ans;
  for (int i = 0; i < n; i++) {
    if (a[i] == paint) {
      a[i] = 1;
      paint = -2;
      continue;
    }
    a[i] = color[a[i]];
  }
  cout << "YES"
       << "\n";
  for (int i = 0; i < a.size(); i++) {
    char vr = 'A';
    if (a[i] == 1) vr = 'B';
    ans.push_back(vr);
  }
  cout << "\n";
  cout << ans << "\n";
}
