#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, n, j;
  string s;
  cin >> n;
  cin >> s;
  int len;
  string temp1, temp2;
  for (i = s.length() - 1; i >= 0; i--) {
    len = temp1.length();
    temp2.clear();
    for (j = 0; j < len / 2; j++) temp2 += temp1[j];
    temp2 += s[i];
    for (; j < len; j++) temp2 += temp1[j];
    temp1.clear();
    for (j = 0; j < temp2.length(); j++) temp1 += temp2[j];
  }
  cout << temp1;
  return 0;
}
