#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,a[61],i,j,k,t;
    cin>>n;
    for(i = 0;i < n;i++){
        cin>>a[i];
    }
    for(i = 1;i < n;i++) {
        for(j = 0;j < n - i;j++){
            if(a[j] > a[j + 1]){
                t = a[j];
                a[j] = a[j + 1];
                a[j + 1] = t;
            }
        }
    }
    for(i = 0;i < n;i = i + 2){
        cout<<a[i]<<" ";
    }
      
    for(i = n - 2;i >= 0;i = i - 2){
        cout<<a[i]<<" ";
    }
}
/**************************************************************
	Problem: 1283
	User: linmiaoling
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/