#include <bits/stdc++.h>
using namespace std;
int dx[] = {0, 0, 1, -1};
int dy[] = {1, -1, 0, 0};
int dx8[] = {0, 0, 1, 1, 1, -1, -1, -1};
int dy8[] = {1, -1, -1, 0, 1, -1, 0, 1};
int n, a[110], frq[110];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  for (int i = 0; i < (n); i++) {
    cin >> a[i];
    frq[a[i]]++;
  }
  int cnt = 0, cn = 0;
  for (int i = 0; i < (101); i++) {
    if (frq[i] && frq[i] >= 3) cn = 1;
    if (frq[i] == 1) {
      cnt++;
    }
  }
  if (cnt % 2 == 0) {
    int k = 1;
    cout << "YES" << endl;
    for (int i = 0; i < (n); i++) {
      if (frq[a[i]] == 1) {
        if (k * 2 <= cnt) {
          cout << "A";
          k++;
        } else
          cout << "B";
      } else
        cout << "B";
    }
  } else if (cn) {
    cout << "YES" << endl;
    cnt++;
    int k = 1, flg = 1;
    for (int i = 0; i < (n); i++) {
      if (frq[a[i]] == 1) {
        if (k * 2 <= cnt) {
          cout << "B";
          k++;
        } else
          cout << "A";
      } else if (flg && frq[a[i]] >= 3) {
        cout << "A";
        flg = 0;
      } else
        cout << "B";
    }
    cout << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
