#include <bits/stdc++.h>
using namespace std;
const long long N = (1e6 + 10);
int main() {
  long long n, o;
  cin >> n;
  string a, s;
  cin >> a;
  o = n;
  while (a.size() > 0) {
    if (n % 2 == 1)
      s += a[0];
    else
      s = a[0] + s;
    a.erase(a.begin());
    n--;
  }
  cout << s << endl;
  return 0;
}
