#include <bits/stdc++.h>
using namespace std;
int a[200];
int c[200];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    c[a[i]]++;
  }
  int s = 0;
  int pp = 0;
  for (int i = 1; i <= 100; i++) {
    if (c[i] == 1) {
      s++;
    } else if (c[i] > 2 && pp == 0) {
      pp = i;
    }
  }
  if (s % 2 == 1 && pp == 0) {
    printf("NO\n");
  } else if (s % 2 == 1 && pp > 0) {
    printf("YES\n");
    int co = 0;
    int bo = 0;
    s = (int)s / 2;
    for (int i = 1; i <= n; i++) {
      if (c[a[i]] == 1 && co < s) {
        printf("A");
        co++;
      } else if (c[a[i]] == 1) {
        printf("B");
      } else if (a[i] == pp && bo == 0) {
        printf("A");
        bo += 10;
      } else {
        printf("B");
      }
    }
    printf("\n");
  } else if (s % 2 == 0) {
    printf("YES\n");
    int co = 0;
    s = s / 2;
    for (int i = 1; i <= n; i++) {
      if (c[a[i]] == 1 && co < s) {
        printf("A");
        co++;
      } else {
        printf("B");
      }
    }
    printf("\n");
  }
}
