#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[104], cntarr[104] = {0};
  cin >> n;
  int cnt = n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    cntarr[a[i]]++;
    if (cntarr[a[i]] > 2) cnt--;
  }
  if (((cnt % 2 == 1) && (cnt == n)) || (cnt == 0)) {
    cout << "NO";
    return 0;
  }
  int cntm = 0, flag = 0;
  cout << "YES\n";
  for (int i = 1; i <= n; i++) {
    if (cntarr[a[i]] == 1) {
      if (cntm % 2 == 0) {
        cout << "A";
      } else {
        cout << "B";
      }
      cntm++;
    } else if ((cnt % 2 == 1) && (flag == 0) && (cntarr[a[i]] != 2)) {
      cout << "B";
      flag = 1;
    } else {
      cout << "A";
    }
  }
  return 0;
}
