# include <iostream>
# include <iomanip>
# include <algorithm>

using namespace std;


int main()
{
   int n;
   cin >> n;
   int num[n];
   for (int i = 0; i < n; i++) cin >> num[i];
   sort(num, num + n);
   for (int i = 0; i < n; i++) {
      cout << string(1, 'A' + num[i] % 26);
   }
   cout << endl;
}