#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  char a[n + 1];
  for (int i = 1; i <= n; i++) cin >> a[i];
  if (n & 1) {
    for (int i = n - 1; i >= 2; i -= 2) cout << a[i];
    for (int i = 1; i <= n; i += 2) cout << a[i];
  } else {
    for (int i = n - 1; i >= 1; i -= 2) cout << a[i];
    for (int i = 2; i <= n; i += 2) cout << a[i];
  }
  return 0;
}
