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