#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  string s, res;
  cin >> n >> s;
  res = s;
  int med = (n - 1) / 2;
  res[med] = s[0];
  for (int t = 1, y = 1; y < n; ++t, y += 2) {
    if (n & 1) {
      if (med - t >= 0) res[med - t] = s[y];
      res[med + t] = (y != n - 1 ? s[y + 1] : s[y]);
    } else {
      if (med + t < n) res[med + t] = s[y];
      if (med - t >= 0) res[med - t] = (y != n - 1 ? s[y + 1] : s[y]);
    }
  }
  cout << res;
}
