#include <bits/stdc++.h>
using namespace std;
int a[123];
int sum[123];
int vis[123];
set<int> V1, V2, V3;
int n;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    sum[a[i]]++;
  }
  for (int i = 1; i <= 100; i++) {
    if (sum[i] == 1)
      V1.insert(i);
    else if (sum[i] == 2)
      V2.insert(i);
    else if (sum[i] >= 3)
      V3.insert(i);
  }
  if (V1.size() % 2 != 0 && V3.empty())
    cout << "NO" << endl;
  else {
    cout << "YES" << endl;
    if (V1.size() % 2 == 0) {
      int ct = 0;
      for (int i = 1; i <= n; i++) {
        if (V1.count(a[i])) {
          if (ct < (int)V1.size() / 2)
            cout << "A";
          else
            cout << "B";
          ct++;
        } else
          cout << "A";
      }
    } else {
      int ct = 0;
      for (int i = 1; i <= n; i++) {
        if (V1.count(a[i])) {
          if (ct < (int)V1.size() / 2)
            cout << "A";
          else
            cout << "B";
          ct++;
        } else if (V2.count(a[i])) {
          if (vis[a[i]] == 0)
            cout << "A";
          else
            cout << "B";
          vis[a[i]]++;
        } else {
          if (a[i] == *V3.begin()) {
            if (vis[a[i]])
              cout << "B";
            else
              cout << "A";
            vis[a[i]]++;
          } else
            cout << "B";
        }
      }
    }
  }
  return 0;
}
