#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  int n;
  cin >> n;
  cin >> s;
  deque<char> dq;
  int sz = s.size();
  if (sz % 2 != 0) {
    int i = 0;
    for (i = 0; i < sz; i++) {
      if (i % 2 == 0) {
        dq.push_back(s[i]);
      } else
        dq.push_front(s[i]);
    }
  } else {
    int j = 0;
    for (j = 0; j < sz; j++) {
      if (j % 2 != 0) {
        dq.push_back(s[j]);
      } else
        dq.push_front(s[j]);
    }
  }
  deque<char>::iterator it;
  for (it = dq.begin(); it < dq.end(); it++) {
    cout << *it;
  }
}
