#include <bits/stdc++.h>
using namespace std;
int main() {
  cin.tie(0);
  ios_base::sync_with_stdio(0);
  deque<char> d;
  int n;
  cin >> n;
  string s;
  cin >> s;
  int fl;
  if (s.size() % 2 == 0)
    fl = 1;
  else
    fl = 0;
  for (int i = 0; i < s.size(); i++) {
    if (fl)
      d.push_front(s[i]);
    else
      d.push_back(s[i]);
    fl = fl ^ 1;
  }
  for (int i = 0; i < s.size(); i++) {
    cout << d.front();
    d.pop_front();
  }
  cout << endl;
}
