/*
TASK: ots
LANG: C++
*/
#include <iostream>
#include <limits.h>
using namespace std;

int N;
int A[1000000];
int B[1000000];

int main()
{
    cin>>N;
    for(int i=0; i<N; i++)
    {
            cin>>A[i];
    }
    sort(A, A+N);
    B[1] = A[1] - A[0];
    B[0] = B[1];
    B[2] = INT_MAX;
    for(int i=2; i<N; i++)
    {
            int _b = B[i];
            B[i] = min(B[i], B[i-2]+A[i]-A[i-1]);
            if(B[i]==_b) {B[i+1] = _b;}
            else {B[i+1] = INT_MAX;}
    }
    cout<<B[N-1]<<'\n';
    return 0;
}
