#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long n;
  cin >> n;
  vector<long long> a(n);
  map<long long, long long> m;
  vector<bool> ans(n);
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    m[a[i]]++;
  }
  long long pos = 0;
  long long z = 0;
  long long o = 0;
  for (long long i = 0; i < n; i++) {
    if (m[a[i]] == 1) {
      ans[i] = (pos & 1);
      pos++;
      z += (ans[i] == 0);
      o += (ans[i] == 1);
    } else
      ans[i] = 0;
  }
  if (z > o) {
    for (long long i = 0; i < n; i++) {
      if (m[a[i]] > 2) {
        ans[i] = 1;
        o++;
        break;
      }
    }
  } else if (o > z) {
    for (long long i = 0; i < n; i++) {
      if (m[a[i]] > 2) {
        ans[i] = 0;
        z++;
        break;
      }
    }
  }
  if (o == z) {
    cout << "YES"
         << "\n";
    for (long long i = 0; i < n; i++) cout << char(ans[i] + 'A');
  } else
    cout << "NO"
         << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long tt = 1;
  while (tt--) {
    solve();
  }
  return 0;
}
