#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(NULL), cout.tie(NULL);
  int n, a[105], b[105]{}, x = 0, y = 0, z = 0;
  char c = 'A', d;
  cin >> n;
  for (int i = 0; i < n; i++) cin >> a[i], b[a[i]]++;
  for (int i = 0; i < 101; i++)
    if (b[i] == 1)
      x++;
    else if (b[i] > 2 && !y)
      y = i;
  if (x % 2 == 0 || y) {
    cout << "YES\n";
    for (int i = 0; i < n; i++)
      if (b[a[i]] == 1) {
        cout << c;
        c = char('A' + 'B' - c);
      } else if (a[i] == y && (x & 1)) {
        if (!z) {
          cout << c;
          c = char('A' + 'B' - c);
          d = c, z = 1;
        } else
          cout << d;
      } else
        cout << 'A';
  } else
    cout << "NO\n";
  return 0;
}
