#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s, soln;
  cin >> s;
  soln = s;
  for (int i = 0, idx = (n - 1) / 2; i < n; i++) {
    soln[idx] = s[i];
    if ((n + i) % 2 == 0)
      idx += (i + 1);
    else if ((n + i) % 2 == 1)
      idx -= (i + 1);
  }
  cout << soln << endl;
  return 0;
}
