#include <bits/stdc++.h>
using namespace std;
const int N = 1002;
int n, a[N];
vector<int> ind[N];
char str[N];
int main() {
  scanf("%d", &n);
  for (int(i) = (1); (i) <= (int)(n); (i)++)
    scanf("%d", &a[i]), ind[a[i]].push_back(i);
  int b = 0;
  for (int(i) = (1); (i) <= (int)(N - 1); (i)++) {
    if ((int)(ind[i]).size() == 1) {
      if (b > 0)
        str[ind[i][0]] = 'B', --b;
      else
        str[ind[i][0]] = 'A', ++b;
    }
    if ((int)(ind[i]).size() == 2) {
      str[ind[i][0]] = 'A', str[ind[i][1]] = 'B';
    }
  }
  for (int(i) = (1); (i) <= (int)(N - 1); (i)++) {
    if ((int)(ind[i]).size() > 2) {
      if (!b) {
        for (int j : ind[i]) {
          str[j] = 'A';
        }
      } else if (b > 0) {
        --b, str[ind[i][0]] = 'B';
        for (int(j) = (1); (j) <= (int)((int)(ind[i]).size() - 1); (j)++)
          str[ind[i][j]] = 'A';
      } else {
        ++b, str[ind[i][0]] = 'A';
        for (int(j) = (1); (j) <= (int)((int)(ind[i]).size() - 1); (j)++)
          str[ind[i][j]] = 'A';
      }
    }
  }
  if (!b)
    printf("YES\n%s\n", str + 1);
  else
    printf("NO\n");
  return 0;
}
