#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string k;
  cin >> k;
  int counter = 0;
  int index_check = n % 2 == 0 ? 0 : 1;
  int index = n - 2;
  bool flag = true;
  if (n == 1) {
    cout << k;
    return 0;
  }
  while (counter < n) {
    counter++;
    cout << k[index];
    if (index == index_check) {
      if (index_check == 1)
        index = 0;
      else
        index++;
      flag = false;
    } else {
      if (flag)
        index -= 2;
      else
        index += 2;
    }
  }
  return 0;
}
