#include <bits/stdc++.h>
int d[1005], vis[1005];
int main() {
  int flag = 0;
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    scanf("%d", &d[i]);
    vis[d[i]]++;
  }
  int ans = 0;
  for (int i = 1; i <= 100; i++) {
    if (vis[i] == 1) {
      ans++;
    }
    if (vis[i] >= 3) {
      flag = 1;
    }
  }
  if (!(ans & 1)) {
    puts("YES");
    int g = 0;
    for (int i = 0; i < n; i++) {
      if (vis[d[i]] == 1 && g) {
        putchar('A');
      } else {
        putchar('B');
      }
      if (vis[d[i]] == 1) {
        g ^= 1;
      }
    }
    puts("");
    return 0;
  }
  if (flag == 0) {
    puts("NO");
    return 0;
  }
  puts("YES");
  int cnt = 0, f = 0;
  for (int i = 0; i < n; i++) {
    if (cnt < (ans >> 1) && vis[d[i]] == 1) {
      putchar('B');
      cnt++;
    } else if (vis[d[i]] >= 3 && f == 0) {
      putchar('B');
      f = 1;
    } else {
      putchar('A');
    }
  }
  puts("");
  return 0;
}
