#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    int N;
    cin >> N;
    
    vector<ll> D(N);
    rep(i, 0, N) cin >> D[i];
    sort(all(D));
    
    rep(i, 0, N) cout << (char)('A' + D[i] % 26);
    cout << '\n';
}