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