#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[n];
  int s[101] = {0};
  for (int i = 0; i < n; i++) cin >> a[i], s[a[i]]++;
  int nice = 0;
  for (int i = 1; i <= 100; i++) {
    if (s[i] == 1) nice++;
  }
  if (nice % 2 == 0) {
    cout << "YES" << endl;
    for (int i = 0; i < n; i++) {
      if (s[a[i]] == 1) {
        if (nice % 2)
          cout << "B";
        else
          cout << "A";
        nice--;
      } else
        cout << "A";
    }
  } else {
    int index = -1;
    for (int i = 1; i <= 100; i++) {
      if (s[i] >= 3) {
        index = i;
        break;
      }
    }
    if (index == -1) {
      cout << "NO";
      return 0;
    }
    cout << "YES" << endl;
    bool flag = false;
    for (int i = 0; i < n; i++) {
      if (a[i] == index && !flag) {
        cout << "A";
        flag = true;
        continue;
      }
      if (s[a[i]] == 1) {
        if (nice % 2)
          cout << "B";
        else
          cout << "A";
        nice--;
      } else
        cout << "B";
    }
  }
}
