#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  long long int n;
  cin >> n;
  long long int a[n];
  for (long long int i = 0; i < n; i++) cin >> a[i];
  sort(a, a + n);
  for (long long int i = 0; i < n; i++)
    if (!(i & 1)) cout << a[i] << " ";
  for (long long int i = n - 1; i >= 0; i--)
    if ((i & 1)) cout << a[i] << " ";
}
