#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string s1 = "", s2 = "";
  cin >> n;
  char arr[n];
  for (int i = 0; i <= n; i++) cin >> arr[i];
  if (n % 2 == 0) {
    for (int i = 0; i < n; i++) {
      if (i % 2 == 0)
        s1 += arr[i];
      else
        s2 += arr[i];
    }
    reverse(s1.begin(), s1.end());
    cout << s1 + s2;
  } else {
    for (int i = 0; i < n; i++) {
      if (i % 2 == 0)
        s1 += arr[i];
      else
        s2 += arr[i];
    }
    reverse(s2.begin(), s2.end());
    cout << s2 + s1;
  }
  return 0;
}
