#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> a(n), f(101);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    f[a[i]]++;
  }
  int nc = 0;
  for (int i = 1; i <= 100; i++) {
    if (f[i] == 1) nc++;
  }
  if (nc % 2 == 0) {
    cout << "YES\n";
    int tag = 0;
    for (int i = 0; i < n; i++) {
      if (f[a[i]] > 1)
        cout << 'A';
      else {
        if (tag)
          cout << 'A';
        else
          cout << 'B';
        tag ^= 1;
      }
    }
    return 0;
  }
  int flag = 0;
  for (int i = 1; i <= 100; i++) {
    if (f[i] > 2) {
      flag = i;
      break;
    }
  }
  if (flag == 0) {
    cout << "NO";
    return 0;
  }
  cout << "YES\n";
  f[flag]--;
  int tag = 0;
  char tmp;
  vector<char> ans(n, '#');
  for (int i = 0; i < n; i++) {
    if (f[a[i]] > 1 && a[i] != flag)
      continue;
    else {
      if (tag)
        ans[i] = 'A';
      else
        ans[i] = 'B';
      tag ^= 1;
      if (a[i] == flag) {
        tmp = ans[i];
        flag = -1;
      }
    }
  }
  for (int i = 0; i < n; i++) {
    if (ans[i] == '#') {
      if (tmp == 'A')
        ans[i] = 'B';
      else
        ans[i] = 'A';
    }
    cout << ans[i];
  }
  return 0;
}
