#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n;
  cin >> n;
  vector<long long> v;
  for (long long i = (0); i < (n); ++i) {
    v.push_back(i);
  }
  vector<long long> v1;
  for (long long i = (0); i < (n); ++i) {
    int index = (v.size() - 1) / 2;
    v1.push_back(v[index]);
    v.erase(v.begin() + index);
  }
  string s;
  cin >> s;
  string ans;
  for (long long i = (0); i < (s.size()); ++i) {
    ans += "0";
  }
  for (long long i = (0); i < (s.size()); ++i) {
    ans[v1[i]] = s[i];
  }
  cout << ans << endl;
  return 0;
}
