#include <bits/stdc++.h>
using namespace std;
int s[109];
int vis[1009];
char pos[1009];
int main() {
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &s[i]);
    vis[s[i]]++;
  }
  int cnt = 0;
  int flag = 0;
  for (int i = 1; i <= n; i++) {
    if (vis[s[i]] == 2)
      pos[i] = 'A';
    else {
      if (vis[s[i]] == 1) {
        cnt++;
        if (!flag) {
          pos[i] = 'A';
          flag = 1;
        } else {
          pos[i] = 'B';
          flag = 0;
        }
      }
    }
  }
  if (cnt % 2 == 0) {
    printf("YES\n");
    for (int i = 1; i <= n; i++) {
      if (pos[i])
        printf("%c", pos[i]);
      else
        printf("A");
    }
    printf("\n");
    return 0;
  }
  int flag1 = 0;
  int vv = 0;
  for (int i = 1; i <= n; i++) {
    if (vis[s[i]] > 2 && !flag1) {
      pos[i] = 'B';
      flag1 = 1;
      vv = 1;
    } else if (vis[s[i]] > 2 && flag1)
      pos[i] = 'A';
  }
  if (vv) {
    printf("YES\n");
    for (int i = 1; i <= n; i++) {
      printf("%c", pos[i]);
    }
    printf("\n");
    return 0;
  }
  printf("NO\n");
}
