#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, cnt1 = 0, cnt3 = 0, cnt2 = 0;
  cin >> n;
  vector<int> arr(n);
  vector<char> ans(n, 'B');
  map<int, int> a;
  for (int i = 0; i < n; ++i) {
    cin >> arr[i];
    a[arr[i]]++;
  }
  for (map<int, int>::iterator it = a.begin(); it != a.end(); ++it) {
    int f = it->first;
    int g = it->second;
    if (g == 1) cnt1++;
    if (g > 2) cnt3++;
  }
  if (cnt1 % 2 and cnt3 == 0) {
    return cout << "NO", 0;
  }
  cout << "YES\n";
  if (cnt1 % 2) {
    bool is = 0;
    int l = 0;
    for (int i = 0; i < n; i++) {
      if (a[arr[i]] > 2 and !is) {
        is = 1;
        ans[i] = 'A';
      }
      if (a[arr[i]] == 1 and l < cnt1 - 1) {
        ans[i] = 'A';
        cnt1--;
        l++;
      }
      cout << ans[i];
    }
    return 0;
  }
  int l = 0;
  for (int i = 0; i < n; i++) {
    if (a[arr[i]] == 1 && l < cnt1) {
      ans[i] = 'A';
      cnt1--;
      l++;
    }
    cout << ans[i];
  }
  return 0;
}
