#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> s(n), check(105, 0), ans(105, -1);
  for (int i = 0; i < n; i++) {
    cin >> s[i];
    check[s[i]]++;
  }
  bool lastA = false;
  int countA = 0, countB = 0;
  for (int i = 1; i < 105; i++) {
    if (check[i] == 1) {
      if (lastA) {
        ans[i] = 1;
        countA++;
      } else {
        ans[i] = 2;
        countB++;
      }
      lastA = !lastA;
    } else if (check[i] != 0)
      ans[i] = 1;
  }
  if (countA == countB) {
    cout << "YES" << endl;
    for (int i = 0; i < n; i++) {
      if (ans[s[i]] == 1)
        cout << "A";
      else if (ans[s[i]] == 2)
        cout << "B";
      else
        cout << "A";
    }
    cout << endl;
  } else {
    if (countA > countB) {
      int rem = abs(countA - countB), i = 1;
      while (i < 105 && rem > 0) {
        if (check[i] > 2) {
          ans[i] = 3;
          rem--;
        }
        i++;
      }
      if (rem > 0)
        cout << "NO" << endl;
      else {
        cout << "YES" << endl;
        for (int i = 0; i < n; i++) {
          if (ans[s[i]] == 1)
            cout << "A";
          else if (ans[s[i]] == 2)
            cout << "B";
          else if (ans[s[i]] == 3) {
            cout << "B";
            ans[s[i]] = 1;
          }
        }
        cout << endl;
      }
    } else {
      int rem = abs(countA - countB), i = 1;
      while (i < 105 && rem > 0) {
        if (check[i] > 2) {
          ans[i] = 3;
          rem--;
        }
        i++;
      }
      if (rem > 0)
        cout << "NO" << endl;
      else {
        cout << "YES" << endl;
        for (int i = 0; i < n; i++) {
          if (ans[s[i]] == 1)
            cout << "A";
          else if (ans[s[i]] == 2)
            cout << "B";
          else if (ans[s[i]] == 3) {
            cout << "A";
            ans[s[i]] = 2;
          }
        }
        cout << endl;
      }
    }
  }
  return 0;
}
