#include <bits/stdc++.h>   using namespace std;   set<int> st[2];   map<int, int> mp;   int ar[110];   int main() {     int n;     cin >> n;     for (int i = 0; i < n; i++) {       cin >> ar[i];       mp[ar[i]]++;     }     int idx = 0;     map<int, int>::iterator it1;     for (it1 = mp.begin(); it1 != mp.end(); it1++) {       if (it1->second == 1) {         st[idx].insert(it1->first);         idx = !idx;       }     }     if (st[0].size() == st[1].size()) {       string ans(n,  A );       for (int i = 0; i < n; i++) {         if (st[1].count(ar[i])) ans[i] =  B ;       }       cout <<  YES n ;       for (int i = 0; i < n; i++) cout << ans[i];       return 0;     } else {       string res(n,  A );       for (int i = 0; i < n; i++) {         if (st[1].count(ar[i])) {           res[i] =  B ;         }       }       int id = -1;       map<int, int>::iterator it;       for (it = mp.begin(); it != mp.end(); it++) {         if (it->second >= 3) {           id = it->first;           break;         }       }       if (id == -1) {         cout <<  NO ;         return 0;       }       bool flag = false;       for (int i = 0; i < n; i++) {         if (ar[i] == id) {           if (!flag) {             flag = true;             res[i] =  B ;           }         }       }       cout <<  YES n ;       for (int i = 0; i < n; i++) {         cout << res[i];       }       return 0;     }     return 0;   }   