#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  long long a[n];
  long long fre[1001] = {0};
  for (long long i = 0; i < n; i++) {
    cin >> a[i];
    fre[a[i]]++;
  }
  long long c = 0, p = 0;
  for (long long i = 0; i < 102; i++) {
    if (fre[i] == 1)
      c++;
    else if (fre[i] > 2)
      p++;
  }
  if (c % 2 and p == 0) {
    cout << "NO";
    return 0;
  }
  char s[n];
  cout << "YES\n";
  if (c % 2) {
    char ch = 'A';
    for (long long i = 0; i < n; i++) {
      if (fre[a[i]] == 1) {
        s[i] = ch;
        if (ch == 'A')
          ch = 'B';
        else
          ch = 'A';
      }
    }
    for (long long i = 0; i < n; i++) {
      if (fre[a[i]] > 2) {
        s[i] = ch;
        if (ch == 'A')
          ch = 'B';
        else
          ch = 'A';
        for (long long j = i + 1; j < n; j++)
          if (a[j] == a[i]) s[j] = ch;
        break;
      }
    }
  } else {
    char ch = 'A';
    for (long long i = 0; i < n; i++) {
      if (fre[a[i]] == 1) {
        s[i] = ch;
        if (ch == 'A')
          ch = 'B';
        else
          ch = 'A';
      } else
        s[i] = 'B';
    }
  }
  for (long long i = 0; i < n; i++) {
    if (s[i] != 'A' and s[i] != 'B') s[i] = 'B';
    cout << s[i];
  }
}
