#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string s;
  deque<char> res;
  cin >> n >> s;
  int middle, i = 1, count = 1;
  res.push_back(s[0]);
  if (n % 2 == 0) {
    res.push_back(s[1]);
    i = 2;
  }
  while (i < n) {
    if (count % 2 == 1)
      res.push_front(s[i]);
    else
      res.push_back(s[i]);
    ++i, ++count;
  }
  for (int i = 0; i < res.size(); ++i) cout << res[i];
  cout << endl;
  return 0;
}
