#ifndef INCLUDED_MAIN
#define INCLUDED_MAIN

#include __FILE__

int main(){
    int n; cin>>n;
    vector<int> d(n);
    rep(i,n) cin>>d[i];
    sort(all(d));
    rep(i,n) d[i]%=26;
    rep(i,n) cout<<char('A'+d[i]);
    cout<<nl;
}

/////// library zone ///////
#else
#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define srep(i,l,r) for(ll i=l;i<=r;i++)
using ll = long long;
using ld = long double;
const ll mod=998244353;
#define vout(v) for(auto i :v) cout<<i<<" ";
#define INF 9223300000000000000ll
#define Winf 5e12
#define nl "\n"
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define vl vector<ll>

ll extgcd(ll a, ll b, ll &x, ll &y) { // ax+by=gcd(a,b) -> x,yを格納
    if (b==0) {
        x=1;
        y=0;
        return a;
    }
    ll d=extgcd(b,a%b,y,x);
    y-=a/b*x;
    return d;
}

ll modinv(ll a, ll mod) { //拡張Euclidによるmodでの逆元, a*u+b(mod)*v=1を解く
	ll b=mod,u=1,v=0;
	while (b) {
		ll t=a/b;
		a-=t*b;
        swap(a,b);
		u-=t*v;
        swap(u,v);
	}
	u%=mod; 
	if (u < 0) u+=mod;
	return u;
}

#endif