#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int TESTS = 1;
  while (TESTS--) {
    long long n, a[101] = {0};
    cin >> n;
    long long x;
    long long v[n];
    vector<long long int> o, one;
    for (long long int i = 0; i < n; i++) {
      cin >> v[i];
      a[v[i]]++;
    }
    for (long long int i = 1; i < 101; i++) {
      if (a[i] == 1) {
        one.push_back(i);
      } else if (a[i] > 2)
        o.push_back(i);
    }
    if (((long long int)one.size() % 2) && (o.empty())) {
      cout << "NO";
    } else {
      vector<char> s(n, 'A');
      for (long long int i = 0; i < (long long int)one.size() / 2; i++) {
        for (long long int j = 0; j < n; j++) {
          if (v[j] == one[i]) s[j] = 'B';
        }
      }
      if ((long long int)one.size() % 2) {
        for (long long int j = 0; j < n; j++) {
          if (v[j] == o[0]) {
            s[j] = 'B';
            break;
          }
        }
      }
      cout << "YES\n";
      for (long long int i = 0; i < n; i++) cout << s[i];
    }
  }
  return 0;
}
