#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, i;
  cin >> n;
  vector<long long int> v[105];
  char c[n];
  for (i = 0; i < n; i++) c[i] = 'A';
  for (i = 0; i < n; i++) {
    long long int y;
    cin >> y;
    v[y].push_back(i);
  }
  long long int single = 0, odd = 0, even = 0;
  for (i = 1; i <= 100; i++) {
    if ((long long int)v[i].size() == 1) single++;
    if ((long long int)v[i].size() % 2 != 0 && (long long int)v[i].size() > 1)
      odd++;
    if ((long long int)v[i].size() % 2 == 0 && (long long int)v[i].size() > 2)
      even++;
  }
  if (single % 2 == 0) {
    single /= 2;
    for (i = 1; i <= 100 && single > 0; i++) {
      if ((long long int)v[i].size() == 1) c[v[i][0]] = 'B', single--;
    }
  } else {
    if (odd == 0 && even == 0) {
      cout << "NO";
      return 0;
    }
    single /= 2;
    for (i = 1; i <= 100 && single > 0; i++) {
      if ((long long int)v[i].size() == 1) c[v[i][0]] = 'B', single--;
    }
    if (odd > 0) {
      for (i = 1; i <= 100; i++) {
        if ((long long int)v[i].size() % 2 != 0 &&
            (long long int)v[i].size() > 1) {
          c[v[i][0]] = 'B';
          break;
        }
      }
    } else {
      for (i = 1; i <= 100; i++) {
        if ((long long int)v[i].size() % 2 == 0 &&
            (long long int)v[i].size() > 2) {
          c[v[i][0]] = 'B';
          break;
        }
      }
    }
  }
  cout << "YES\n";
  for (i = 0; i < n; i++) cout << c[i];
}
