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

using i64 = long long;

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    auto solve = [&]() {
        int n;
        cin >> n;

        vector<int> a(n);
        for (int i = 0; i < n; i++) {
            cin >> a[i];
        }

        sort(a.begin(), a.end());

        for (int i = 0; i < n; i++) {
            cout << char('A' + a[i] % 26);
        }
        cout << '\n';
    };
    
    solve();
    
    return 0;
}