#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string inp;
  cin >> inp;
  string out = inp;
  int indx = n - 1;
  for (int i = n - 1; i >= 0; i -= 2) {
    out[indx--] = inp[i];
  }
  indx = 0;
  for (int i = n - 2; i >= 0; i -= 2) {
    out[indx++] = inp[i];
  }
  out[n] = '\0';
  cout << out;
  return 0;
}
