#include <bits/stdc++.h>
using namespace std;
int n;
string s, x;
deque<char> de;
int main() {
  scanf("%d", &n);
  cin >> s;
  if (n % 2 == 0) {
    for (int i = 0; i < n; i++) {
      if (i % 2 == 0)
        de.push_front(s[i]);
      else
        de.push_back(s[i]);
    }
  } else {
    for (int i = 0; i < n; i++) {
      if (i % 2 == 0)
        de.push_back(s[i]);
      else
        de.push_front(s[i]);
    }
  }
  while (!de.empty()) x += de.front(), de.pop_front();
  cout << x;
  return 0;
}
