#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  string s, t = "";
  int n, i, f;
  cin >> n >> s;
  t = s[0];
  if (n % 2 == 1)
    f = 1;
  else
    f = 0;
  for (i = 1; i < s.length(); i++) {
    if (f)
      t = s[i] + t;
    else
      t = t + s[i];
    f = !f;
  }
  cout << t << endl;
}
