#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, i, j;
  scanf("%d", &N);
  int arr[N], check[101] = {
                  0,
              };
  for (i = 0; i < N; i++) scanf("%d", &arr[i]);
  for (i = 0; i < N; i++) check[arr[i]]++;
  int one = 0, more = 0, tmp, rec = 0;
  for (i = 1; i <= 100; i++) {
    if (check[i] == 1) one++;
    if (check[i] > 2) more++;
  }
  if (more == 0 && one % 2 == 1)
    printf("NO");
  else {
    printf("YES\n");
    if (one % 2 == 0) {
      tmp = -1;
      for (i = 1; i <= 100; i++) {
        if (check[i] == 1) {
          check[i] = tmp;
          if (tmp == -1)
            tmp = -2;
          else
            tmp = -1;
        }
      }
      for (i = 0; i < N; i++) {
        if (check[arr[i]] >= 0) printf("A");
        if (check[arr[i]] == -1) printf("B");
        if (check[arr[i]] == -2) printf("A");
      }
    } else {
      tmp = -1;
      for (i = 1; i <= 100; i++) {
        if (check[i] == 1) {
          check[i] = tmp;
          if (tmp == -1)
            tmp = -2;
          else
            tmp = -1;
        }
        if (check[i] > 2 && rec == 0) rec = i;
      }
      for (i = 0; i < N; i++) {
        if (check[arr[i]] >= 0) {
          if (arr[i] == rec) {
            printf("A");
            rec = 0;
          } else
            printf("B");
        }
        if (check[arr[i]] == -1) printf("B");
        if (check[arr[i]] == -2) printf("A");
      }
    }
  }
}
