#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  string left = "", right = "";
  bool isLeft = (n % 2 == 1 ? false : true);
  for (int i = 0; i < n; ++i) {
    if (isLeft) {
      left = s[i] + left;
      isLeft = !isLeft;
    } else {
      right += s[i];
      isLeft = !isLeft;
    }
  }
  cout << left << right << endl;
  return 0;
}
