#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(a);i>(b);i--)
#define ALL(v) (v).begin(),(v).end()
typedef long long int ll; typedef pair<ll, ll> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<typename A,size_t N,typename T>void Fill(A(&array)[N],const T &val){fill((T*)array, (T*)(array+N), val);}
const int inf = INT_MAX / 2; const ll INF = LLONG_MAX / 2;
//template end



int main(){
    int n; scanf("%d",&n);
    vector<int> a(n);
    rep(i,0,n)scanf("%d",&a[i]);
    sort(ALL(a));
    if(n<=3){
        if(n==2)printf("%d\n",a[1]-a[0]);
        if(n==3)printf("%d\n",a[2]-a[0]);
        return 0;
    }
    int dp[100010]; Fill(dp,inf);
    dp[1]=a[1]-a[0],dp[2]=a[2]-a[0];
    rep(i,3,n)rep(k,2,4){
        chmin(dp[i],dp[i-k]+a[i]-a[i-k+1]);
    }
    printf("%d\n",dp[n-1]);
    return 0;
}