#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n;
  cin >> n;
  vector<int> s(n + 1);
  for (int i = 1; i <= n; ++i) {
    cin >> s[i];
  }
  map<int, int> mp;
  set<int> a;
  set<int> b;
  for (int i = 1; i <= n; ++i) {
    ++mp[s[i]];
  }
  bool p = true;
  for (pair<int, int> z : mp) {
    int x = z.first;
    int y = z.second;
    if (y == 1) {
      if (p) {
        a.insert(x);
      } else {
        b.insert(x);
      }
      p = !p;
    }
  }
  if (a.size() == b.size()) {
    cout << "YES\n";
    for (int i = 1; i <= n; ++i) {
      if (a.count(s[i]) == 1) {
        cout << "A";
      } else {
        cout << "B";
      }
    }
    cout << "\n";
  } else {
    int p = 0;
    for (pair<int, int> z : mp) {
      int x = z.first;
      int y = z.second;
      if (y > 2) {
        p = x;
        break;
      }
    }
    if (p == 0) {
      cout << "NO\n";
    } else {
      cout << "YES\n";
      bool q = false;
      for (int i = 1; i <= n; ++i) {
        if (a.count(s[i]) == 1) {
          cout << "A";
        } else if (s[i] == p) {
          if (q == false) {
            cout << "B";
            q = true;
          } else {
            cout << "A";
          }
        } else {
          cout << "B";
        }
      }
      cout << "\n";
    }
  }
  return 0;
}
