#include <bits/stdc++.h>
using namespace std;
char a[2005];
char temp[2005];
int main() {
  int n;
  cin >> n;
  cin >> a;
  int start = (n - 1) / 2;
  temp[start] = a[0];
  int i = 1, cnt = 1;
  while (cnt < n) {
    if (n % 2 == 0) {
      temp[start + i] = a[cnt++];
      temp[start - i] = a[cnt++];
      i++;
    } else {
      temp[start - i] = a[cnt++];
      temp[start + i] = a[cnt++];
      i++;
    }
  }
  for (int i = 0; i < n; ++i) cout << temp[i];
  return 0;
}
