#include <bits/stdc++.h>
using namespace std;
int main() {
  {
    ios ::sync_with_stdio(false);
    cin.tie(0);
  };
  long long n, i, j, k, p1, p2;
  string s;
  cin >> n >> s;
  char t[n];
  i = 0;
  if (n % 2) {
    t[n / 2] = s[0];
    p1 = n / 2 - 1;
    p2 = n / 2 + 1;
    i++;
  } else {
    p1 = n / 2 - 1;
    p2 = n / 2;
  }
  for (j = 0; j < n / 2; j++) {
    t[p1] = s[i];
    i++;
    p1--;
    t[p2] = s[i];
    i++;
    p2++;
  }
  for (i = 0; i < n; i++) cout << t[i];
  cout << "\n";
}
