#include <bits/stdc++.h>
using namespace std;
int n;
string S;
int main() {
  cin >> n;
  cin >> S;
  string res = "";
  int L = 0;
  if (n % 2 == 0) L = 1;
  int i = 0;
  while (i < n) {
    if (L)
      res = S[i] + res;
    else
      res = res + S[i];
    i++;
    L = !L;
  }
  cout << res << "\n";
}
