#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e4 + 10;
const long long MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const long long LLINF = 0x3f3f3f3f3f3f3f3f;
const long double EPS = 1e-8;
const long double PI = acos(-1);
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  int n, x;
  cin >> n;
  vector<bool> ans(n, false);
  map<int, vector<int> > m;
  for (int i = 0; i < n; i++) {
    cin >> x;
    m[x].push_back(i);
  }
  int l = 0, p = 0;
  for (auto v : m) {
    int len = v.second.size();
    if (len == 1)
      l++;
    else if (len > 2)
      p++;
  }
  bool A = true;
  if (l % 2 == 0) {
    for (auto v : m) {
      int len = v.second.size();
      if (len == 1) {
        ans[v.second[0]] = A;
        A = !A;
      }
    }
  } else {
    bool foi = false;
    if (p == 0) {
      cout << "NO\n";
      return 0;
    }
    for (auto v : m) {
      int len = v.second.size();
      if (len == 1) {
        ans[v.second[0]] = A;
        A = !A;
      } else if (len > 2) {
        for (auto vv : v.second) {
          if (!foi) {
            ans[vv] = 0;
            foi = true;
          } else
            ans[vv] = 1;
        }
      }
    }
  }
  cout << "YES\n";
  for (int i = 0; i < n; i++) cout << (ans[i] ? 'A' : 'B');
  cout << '\n';
  return 0;
}
