#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  list<char> li;
  int n;
  string s;
  cin >> n >> s;
  bool l = 0, r = 0;
  li.push_back(s[0]);
  if (n & 1) {
    l = 1;
  } else
    r = 1;
  for (int i = 1; i < n; i++) {
    if (l) {
      li.push_front(s[i]);
      l = 0;
      r = 1;
    } else {
      li.push_back(s[i]);
      r = 0;
      l = 1;
    }
  }
  for (auto i : li) cout << i;
  cout << '\n';
  return 0;
}
