#include <bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
	int n;
	cin>>n;
	int t[n];
	vector <int> a,b;
	for (int i=0;i<n;i++){
		cin>>t[i];
	}
	sort(t,t+n);
	for (int i=0;i<n;i++){
		if (i%2==0){
			a.push_back(t[i]);
		}
		else {
			b.push_back(t[i]);
		}
	}
	int ans=0;
	int na=a.size(),nb=b.size();
	for (int i=0;i<na-1;i++){
		ans=max(ans,abs(a[i]-a[i+1]));
	}
	ans=max(ans,abs(a[na-1]-b[nb-1]));
	for (int i=0;i<nb-1;i++){
		ans=max(ans,abs(b[i]-b[i+1]));
	}
	cout<<ans<<endl;
	reverse(b.begin(),b.end());
	for (int i=0;i<na;i++){
		cout<<a[i]<<' ';
	}
	for (int i=0;i<nb;i++){
		cout<<b[i]<<' ';
	}
	return 0;
}

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