#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  string t[n];
  int j = 0, k = n - 1;
  int flag = 0;
  for (int i = n - 1; i >= 0; i--) {
    if (flag == 0) {
      t[k] = s[i];
      k--;
      flag = 1;
    } else if (flag == 1) {
      t[j] = s[i];
      j++;
      flag = 0;
    }
  }
  for (int i = 0; i < n; i++) cout << t[i];
  return 0;
}
