#include <bits/stdc++.h>
using namespace std;
struct node {
  int id, num;
} b[150];
int a[150], w1[150], w2[150];
int main() {
  int n, i, x1, x2, k;
  scanf("%d", &n);
  for (i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    b[a[i]].id = i;
    b[a[i]].num++;
  }
  x1 = 0;
  x2 = 0;
  for (i = 1; i <= 100; i++) {
    if (!b[i].num) continue;
    if (b[i].num == 1) {
      x1++;
      w1[x1] = b[i].id;
    } else if (b[i].num >= 3) {
      x2++;
      w2[x2] = b[i].id;
    }
  }
  sort(w1 + 1, w1 + 1 + x1);
  if (x1 % 2 == 0 || x2 >= 1) {
    printf("YES\n");
    k = 1;
    for (i = 1; i <= n; i++)
      if (w1[k] == i) {
        if (k % 2 == 1)
          printf("B");
        else
          printf("A");
        k++;
      } else if (x1 % 2 != 0 && w2[1] == i)
        printf("A");
      else
        printf("B");
  } else
    printf("NO\n");
  return 0;
}
