#include <bits/stdc++.h>
using namespace std;
const int maxn = 200005;
long long int fast_pow(long long int x, long long int y) {
  long long int ret = 1;
  while (y > 0) {
    if (y % 2 == 1) {
      ret *= x;
    }
    x *= x;
    y /= 2;
  }
  return ret;
}
long long int max(long long int x, long long int y) { return x > y ? x : y; }
long long int min(long long int x, long long int y) { return x < y ? x : y; }
long long int exgcd(long long int a, long long int b) {
  if (b == 0) return a;
  return exgcd(b, a % b);
}
int a[maxn], b[maxn], c[maxn];
int main() {
  for (int i = 0; i < 200; i++) c[i] = 105;
  int n;
  scanf("%d", &n);
  for (int i = 1; i <= n; i++) {
    scanf("%d", &a[i]);
    b[a[i]]++;
  }
  if (n == 2) {
    printf("YES\n");
    printf("AB\n");
    return 0;
  }
  int ans1 = 0, ans2 = 0;
  for (int i = 1; i <= 100; i++) {
    if (b[i] == 1)
      ans1++;
    else if (b[i] >= 3)
      ans2++;
  }
  if (ans1 % 2 == 1 && ans2 == 0)
    printf("NO\n");
  else {
    printf("YES\n");
    int ans = 0;
    for (int i = 1; i <= n; i++) {
      if (b[a[i]] == 1) {
        c[i] = ans % 2;
        ans++;
      }
    }
    if (ans1 % 2 == 1)
      for (int i = 1; i <= n; i++)
        if (b[a[i]] >= 3) {
          c[i] = 1;
          break;
        }
    for (int i = 1; i <= n; i++) {
      if (c[i] == 0 || c[i] == 105)
        printf("A");
      else
        printf("B");
    }
    printf("\n");
  }
  return 0;
}
