#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000005
#define Inf64 4000000000000000001LL

int main(){
	
	int n;
	cin>>n;
	string ans = "";
	vector<int> t(n);
	rep(i,n){
		cin>>t[i];
	}
	sort(t.begin(),t.end());
	rep(i,t.size())ans += 'A' + (t[i]%26);
	cout<<ans<<endl;
	
	return 0;
}