#include <bits/stdc++.h>
using namespace std;
int chek(string& s, int v) {
  int ans = 0, arg = (s.size() - v + 1);
  bool r = 1;
  for (int i = 0; i < arg; ++i) {
    r = 1;
    for (int j = i; j < i + v - 1; ++j)
      if (s[j] != s[j + 1]) r = 0;
    if (r) ans++;
  }
  return ans;
}
int main() {
  string s;
  long long int n, m;
  long long int q = 0;
  cin >> n;
  vector<int> v, w(n);
  for (int i = 0; i < n; ++i) {
    cin >> m;
    v.push_back(m);
  }
  for (int i = v.size() - 1; i >= 0; --i) {
    m = chek(s, i + 1);
    for (int j = m; j < v[i]; ++j) {
      for (int k = 0; k < i + 1; ++k) s.push_back((char)((q % 26) + 97));
      ++q;
    }
  }
  cout << s;
}
