#include <bits/stdc++.h>
using namespace std;
const int N = 200010;
deque<char> str;
int n;
string k;
int main() {
  cin >> n;
  cin >> k;
  int bk = n & 1;
  for (int i = 0; i < k.size(); ++i) {
    if (bk) {
      str.push_back(k[i]);
    } else {
      str.push_front(k[i]);
    }
    bk = !bk;
  }
  while (str.size()) {
    printf("%c", str.front());
    str.pop_front();
  }
  puts("");
  return 0;
}
