#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n;
  cin >> n;
  long long int a[n];
  long long int f[101] = {0};
  for (long long int i = 0; i < n; i++) {
    cin >> a[i];
    f[a[i]]++;
  }
  long long int nice[101] = {0};
  long long int nc = 0;
  for (long long int i = 0; i < n; i++) {
    if (f[a[i]] == 1) {
      nice[a[i]] = 1;
      nc++;
    }
  }
  if (nc % 2 == 0) {
    cout << "YES" << endl;
    long long int prev = 1;
    for (long long int i = 0; i < n; i++) {
      if (nice[a[i]] and prev == 1) {
        cout << "A";
        prev = 0;
      } else if (nice[a[i]] and prev == 0) {
        cout << "B";
        prev = 1;
      } else if (!nice[a[i]])
        cout << "A";
    }
  } else {
    long long int ind = -1;
    for (long long int i = 0; i < n; i++) {
      if (!nice[a[i]] and f[a[i]] > 2) {
        ind = i;
        break;
      }
    }
    if (ind == -1) {
      cout << "NO";
    } else {
      cout << "YES" << endl;
      long long int prev = 1;
      for (long long int i = 0; i < n; i++) {
        if (nice[a[i]] and prev == 1) {
          cout << "A";
          prev = 0;
        } else if (nice[a[i]] and prev == 0) {
          cout << "B";
          prev = 1;
        } else if (!nice[a[i]] and i == ind)
          cout << "B";
        else if (!nice[a[i]] and i != ind)
          cout << "A";
      }
    }
  }
}
