#include <bits/stdc++.h>   using namespace std;   const int N = 109;   int n;   int a[N];   map<int, int> m;   set<int> s[2];   int main() {     int n;     cin >> n;     for (int i = 0; i < n; ++i) {       cin >> a[i];       m[a[i]]++;     }     int pos = 0;     for (auto p : m)       if (p.second == 1) {         s[pos].insert(p.first);         pos = 1 - pos;       }     if (s[0].size() == s[1].size()) {       string res(n,  A );       for (int i = 0; i < n; ++i)         if (s[1].count(a[i])) res[i] =  B ;       cout <<  YES  << endl;       for (auto c : res) cout << c;       cout << endl;       return 0;     } else {       assert(int(s[0].size()) - 1 == int(s[1].size()));       string res(n,  A );       for (int i = 0; i < n; ++i)         if (s[1].count(a[i])) res[i] =  B ;       int id = -1;       for (auto p : m)         if (p.second >= 3) {           id = p.first;           break;         }       if (id == -1) {         cout <<  NO  << endl;         return 0;       }       bool flag = false;       for (int i = 0; i < n; ++i) {         if (a[i] == id)           if (!flag) {             flag = true;             res[i] =  B ;           }       }       cout <<  YES  << endl;       for (auto c : res) cout << c;       cout << endl;       return 0;     }     return 0;   }   