#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, s;
  string c;
  cin >> n >> c;
  s = n;
  string r = "";
  while (n > 0) {
    if (n % 2 == 0) {
      string y = "";
      y += c[s - n];
      y += r;
      r = y;
    } else {
      r += c[s - n];
    }
    n--;
  }
  cout << r;
  return 0;
}
