#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  string s;
  cin >> n >> s;
  string ans;
  for (int i = 0; i < n; ++i) {
    if ((n - i) % 2 != 0)
      ans = ans + s[i];
    else
      ans = s[i] + ans;
  }
  cout << ans;
}
