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