#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, x;
  cin >> n;
  x = (n + 1) / 2;
  string s, even, odd;
  cin >> s;
  for (int i = 0; i < n; i++) {
    if (i % 2 == 0)
      odd.push_back(s[i]);
    else
      even.push_back(s[i]);
  }
  if (n <= 2) {
    cout << s << endl;
  } else {
    if (n % 2 == 0) {
      reverse(odd.begin(), odd.end());
      for (int i = 0; i < x; i++) {
        odd.push_back(even[i]);
      }
      even = odd;
    } else if (n % 2 == 1) {
      reverse(even.begin(), even.end());
      for (int i = 0; i < x; i++) {
        even.push_back(odd[i]);
      }
    }
    cout << even << endl;
  }
  return 0;
}
