#include <bits/stdc++.h>
using namespace std;
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  while (!isdigit(ch)) {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (isdigit(ch)) {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
int Hsh[110], cnt1, cnt2, A[110], B[110];
int main() {
  int n = read();
  for (int i = 1; i <= n; i++) {
    int x = read();
    A[i] = x;
    Hsh[x]++;
    if (Hsh[x] == 1) cnt1++;
    if (Hsh[x] == 2) cnt1--;
    if (Hsh[x] == 3) cnt2++;
  }
  if (cnt1 % 2 == 1 && cnt2 == 0) {
    puts("NO");
    return 0;
  }
  int t = 0, fl = 0;
  for (int i = 1; i <= n; i++) {
    if (Hsh[A[i]] == 1) B[i] = t % 2 + 1, t++;
    if (Hsh[A[i]] == 2) B[i] = 1;
    if (Hsh[A[i]] >= 3) {
      if (fl == 0 && cnt1 % 2 == 1)
        B[i] = 2, fl = 1;
      else
        B[i] = 1;
    }
  }
  puts("YES");
  for (int i = 1; i <= n; i++)
    if (B[i] == 1)
      printf("A");
    else
      printf("B");
}
