#include <bits/stdc++.h>
using namespace std;
int n, suma, sumb;
int sum[105];
bool t[105], flag;
vector<int> num[105];
int main() {
  scanf("%d", &n);
  int v;
  for (int i = 1; i <= n; i++) {
    scanf("%d", &v);
    sum[v]++;
    num[v].push_back(i);
  }
  for (int i = 1; i <= 100; i++) {
    if (sum[i] == 1) {
      suma++;
      continue;
    }
    if (sum[i] == 2) continue;
    if (sum[i] >= 3) {
      sumb++;
      continue;
    }
  }
  if (suma & 1 && !sumb) {
    printf("NO");
    return 0;
  }
  if (suma & 1) {
    suma /= 2;
    flag = true;
    for (int i = 1; i <= 100; i++) {
      if (sum[i] == 1 && suma) {
        t[num[i][0]] = true;
        suma--;
      }
      if (sum[i] >= 3 && flag) {
        t[num[i][0]] = true;
        flag = false;
      }
    }
  } else {
    suma /= 2;
    for (int i = 1; i <= 100; i++) {
      if (sum[i] == 1 && suma) {
        t[num[i][0]] = true;
        suma--;
      }
    }
  }
  printf("YES\n");
  for (int i = 1; i <= n; i++)
    if (t[i])
      printf("A");
    else
      printf("B");
  return 0;
}
