#include <bits/stdc++.h>
using namespace std;
long long n, tmp, skrng, awal, akhir;
string s, t;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  cin >> s;
  t = s;
  tmp = 0;
  skrng = (n - 1) / 2;
  while (tmp < n) {
    if (n % 2 == 0 && tmp == 0) {
      awal = skrng;
      akhir = skrng + 1;
      t[awal] = s[tmp];
      awal--;
      tmp++;
      t[akhir] = s[tmp];
      akhir++;
      tmp++;
    } else if (n % 2 == 0 && tmp > 0) {
      t[awal] = s[tmp];
      awal--;
      tmp++;
      t[akhir] = s[tmp];
      tmp++;
      akhir++;
    } else if (n % 2 == 1 && tmp == 0) {
      t[skrng] = s[tmp];
      awal = skrng - 1;
      akhir = skrng + 1;
      tmp++;
    } else if (n % 2 == 1 && tmp > 0) {
      t[awal] = s[tmp];
      awal--;
      tmp++;
      t[akhir] = s[tmp];
      akhir++;
      tmp++;
    }
  }
  cout << t << '\n';
  return 0;
}
