#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  string s, t;
  cin >> s;
  for (int i = 0; i < n; i++) {
    if ((n - i) & 1)
      t += s[i];
    else
      t = s[i] + t;
  }
  cout << t << endl;
  return 0;
}
