#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9 + 5;
const long long LINF = 1e18 + 5;
const double eps = 1e-9;
fstream fin, fout;
int main() {
  int n;
  cin >> n;
  vector<int> q(n);
  for (int &i : q) cin >> i;
  vector<int> one;
  vector<char> v(n, false);
  int d = -1;
  map<int, int> z;
  for (int i = 0; i < n; i++) z[q[i]]++;
  for (int i = 0; i < n; i++)
    if (z[q[i]] == 1)
      one.push_back(i);
    else if (z[q[i]] > 2)
      d = i;
  for (int i = 0; i < one.size() / 2; i++) v[one[i]] = 1;
  bool ans = 1;
  if (one.size() % 2 == 1) {
    if (d == -1)
      ans = 0;
    else
      v[d] = 1;
  }
  if (ans) {
    cout << "YES" << endl;
    for (int i = 0; i < n; i++) cout << char('A' + v[i]);
  } else
    cout << "NO";
}
