#include <bits/stdc++.h>
using namespace std;
int n;
int a[101];
int c[101];
char b[101];
int tw;
int cnt;
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &a[i]);
    c[a[i]]++;
  }
  for (int i = 1; i < 101; i++) {
    if (c[i] == 1) {
      cnt++;
    } else if (c[i] == 2) {
      tw++;
    }
  }
  if (n - cnt - tw < 3 && n % 2 == 1) {
    cout << "NO\n";
    return 0;
  }
  cout << "YES\n";
  if (cnt % 2 == 0) {
    int cur = 0;
    for (int i = 0; i < n; i++) {
      if (c[a[i]] == 1) {
        cur++;
        if (cur <= cnt / 2) {
          cout << 'A';
        } else {
          cout << 'B';
        }
      } else {
        cout << 'A';
      }
    }
  } else {
    int cur = 0;
    int ok = 0;
    for (int i = 0; i < n; i++) {
      if (c[a[i]] == 1) {
        cur++;
        if (cur <= cnt / 2) {
          cout << 'A';
        } else {
          cout << 'B';
        }
      } else if (!ok && c[a[i]] >= 3) {
        ok++;
        cout << 'A';
      } else {
        cout << 'B';
      }
    }
  }
}
