#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  vector<int> b(n);
  for (int i = 0; i < n; ++i) {
    b[i] = i;
  }
  vector<int> a(n);
  for (int i = 0; i < n; ++i) {
    int ind = (b.size() + 1) / 2 - 1;
    a[i] = b[ind];
    b.erase(b.begin() + ind);
  }
  vector<char> ans(n);
  for (int i = 0; i < (int)s.size(); ++i) {
    ans[a[i]] = s[i];
  }
  for (int i = 0; i < (int)s.size(); ++i) {
    cout << ans[i];
  }
  cout << endl;
  return 0;
}
