#include <bits/stdc++.h>
using namespace std;
set<int> st[2];
map<int, int> mp;
int ar[110];
int main() {
  int n;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> ar[i];
    mp[ar[i]]++;
  }
  int idx = 0;
  map<int, int>::iterator it1;
  for (it1 = mp.begin(); it1 != mp.end(); it1++) {
    if (it1->second == 1) {
      st[idx].insert(it1->first);
      idx = !idx;
    }
  }
  if (st[0].size() == st[1].size()) {
    string ans(n, 'A');
    for (int i = 0; i < n; i++) {
      if (st[1].count(ar[i])) ans[i] = 'B';
    }
    cout << "YES\n";
    for (int i = 0; i < n; i++) cout << ans[i];
    return 0;
  } else {
    string res(n, 'A');
    for (int i = 0; i < n; i++) {
      if (st[1].count(ar[i])) {
        res[i] = 'B';
      }
    }
    int id = -1;
    map<int, int>::iterator it;
    for (it = mp.begin(); it != mp.end(); it++) {
      if (it->second >= 3) {
        id = it->first;
        break;
      }
    }
    if (id == -1) {
      cout << "NO";
      return 0;
    }
    bool flag = false;
    for (int i = 0; i < n; i++) {
      if (ar[i] == id) {
        if (!flag) {
          flag = true;
          res[i] = 'B';
        }
      }
    }
    cout << "YES\n";
    for (int i = 0; i < n; i++) {
      cout << res[i];
    }
    return 0;
  }
  return 0;
}
