#include <bits/stdc++.h>
using namespace std;
int n, s[105], vis[105], Num[105], num, num1;
int main() {
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &s[i]);
    Num[s[i]]++;
  }
  for (int i = 1; i <= 100; i++) {
    if (Num[i] == 1) num1++;
    if (Num[i] >= 3) num++;
  }
  if (num == 0 && num1 % 2 == 1)
    printf("NO\n");
  else {
    printf("YES\n");
    if (num1 % 2 == 0) {
      int now = 0;
      for (int i = 1; i <= n; i++) {
        if (Num[s[i]] == 1) {
          if (now)
            printf("A"), now ^= 1;
          else
            printf("B"), now ^= 1;
        } else
          printf("A");
      }
    } else {
      int flag = 0;
      int now = 0;
      for (int i = 1; i <= n; i++) {
        if (Num[s[i]] == 1) {
          if (now)
            printf("A"), now ^= 1;
          else
            printf("B"), now ^= 1;
        } else {
          if (!flag && Num[s[i]] >= 3) {
            flag = 1;
            printf("A");
          } else
            printf("B");
        }
      }
    }
  }
}
