#include <bits/stdc++.h>
using namespace std;
int n, a[101], x, y, s[101], f[101];
int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) cin >> a[i], s[a[i]]++;
  for (int i = 1; i <= 100; i++)
    if (s[i] == 1)
      x++;
    else if (s[i] > 2)
      y++;
  if (x % 2 == 1 && y == 0)
    cout << "NO";
  else {
    cout << "YES" << endl;
    int j = 1;
    for (int i = 1; i <= x / 2; j++)
      if (s[a[j]] == 1) f[j] = 1, i++;
    if (x % 2 == 1)
      for (int i = 1; i <= n; i++)
        if (s[a[i]] > 2) {
          f[i] = 1;
          break;
        }
    for (int i = 1; i <= n; i++)
      if (f[i] == 1)
        cout << 'A';
      else
        cout << 'B';
  }
  return 0;
}
