#include <bits/stdc++.h>
using namespace std;
int main() {
  int l, k = 0, c = 0;
  cin >> l;
  string r, s;
  cin >> s;
  r.reserve(l);
  for (int i = l - 1; i >= 0; i--) {
    if (c) {
      r[k] = s[i];
      c = 0;
      k++;
    } else {
      r[l - k - 1] = s[i];
      c = 1;
    }
  }
  r[l] = '\0';
  printf("%s", r.begin());
  return 0;
}
