#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  deque<char> v;
  cin >> s;
  for (int i = 0; i < s.size(); i++) {
    if (i % 2 == 0)
      v.push_back(s[i]);
    else
      v.push_front(s[i]);
  }
  if (n % 2 == 0)
    for (int i = n - 1; i >= 0; i--) cout << v[i];
  else
    for (int i = 0; i < n; i++) cout << v[i];
  return 0;
}
