#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, i, j, k;
  cin >> n;
  char s1[n + 10], s2[n + 10];
  cin >> s1;
  if (n % 2 == 1) {
    j = n / 2;
    k = j;
  } else {
    j = n / 2 - 1;
    k = j;
  }
  s2[j] = s1[0];
  for (i = 1; i < n; i++) {
    if ((n - i - 1) % 2 == 0) {
      j++;
      s2[j] = s1[i];
    } else {
      k--;
      s2[k] = s1[i];
    }
  }
  for (i = 0; i < n; i++) {
    cout << s2[i];
  }
  cout << endl;
  return 0;
}
