#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int64_t n, i;
  cin >> n;
  string s;
  cin >> s;
  string ans = "";
  ans = ans + s[0];
  bool st = true;
  if ((n - 1) & 1) {
    st = false;
  }
  for (i = 1; i < n; i++) {
    if (st) {
      ans = s[i] + ans;
      st = false;
    } else {
      ans = ans + s[i];
      st = true;
    }
  }
  cout << ans;
  return 0;
}
