#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int n;
  cin >> n;
  cin >> s;
  string R;
  R.assign("", s.size());
  int id = n - 1;
  bool ok = 0;
  int i1 = 0, i2 = n - 1;
  for (int i = n - 1; i >= 0; i--) {
    if (!ok) {
      ok = !ok;
      R[i2] = s[i];
      i2--;
    } else {
      ok = !ok;
      R[i1] = s[i];
      i1++;
    }
  }
  cout << R << endl;
  return 0;
}
