#include <bits/stdc++.h>
using namespace std;
const int maxm = 105;
int flag[maxm], a[maxm], b[maxm];
char str[maxm];
int main() {
  int n, j, k, sum, i, rev;
  sum = rev = 0;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    flag[a[i]]++;
  }
  for (i = 1; i <= n; i++) {
    if (flag[a[i]] == 1) b[++sum] = a[i];
    if (flag[a[i]] > 2) rev++;
  }
  if (sum % 2 == 1 && rev == 0) {
    printf("NO\n");
    return 0;
  }
  int now = 1;
  for (i = 1; i <= n; i++) {
    if (flag[a[i]] == 1) {
      if (now <= sum / 2)
        str[i] = 'A';
      else
        str[i] = 'B';
      now++;
    } else if (flag[a[i]] > 2 && sum % 2 == 1)
      str[i] = 'A', sum--;
    else
      str[i] = 'B';
  }
  printf("YES\n");
  for (i = 1; i <= n; i++) printf("%c", str[i]);
  printf("\n");
  return 0;
}
