#include <bits/stdc++.h>
using namespace std;

#include <atcoder/all>
using namespace atcoder;

using ll = long long;
using mint = modint998244353;

int main() {
  int N;
  cin >> N;
  vector<int> D(N);
  for(int &x : D) cin >> x;
  sort(D.begin(), D.end());
  for(int &x : D) cout << (char)('A' + x % 26);
}