#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll=long long;

int main()
{
    int n;
    cin>>n;
    vector<int> d(n);
    for(int i=0;i<n;i++)cin>>d[i];
    sort(d.begin(),d.end());
    for(int i=0;i<n;i++)cout<<(char)('A'+(d[i]%26));
    cout<<endl;
    return 0;
}