#include <bits/stdc++.h>
using namespace std;
using pii=pair<int,int>;
using i64=int_fast64_t;

int n;
i64 dp[1<<17];
int hei[1<<17];
int num[1<<17];
const i64 inf=1e18;

int main() {
    cin>>n;
    map<int,int> mp;
    for(int i=0; i<n; ++i) {
        int y; cin>>y;
        mp[y]++;
    }
    n=0;
    for(auto &p:mp) {
        tie(hei[n],num[n])=p;
        num[n]--;
        ++n;
    }
    fill(dp+1,dp+n+1,inf);
    dp[0]=0;
    for(int i=0; i<n; ++i) {
        if(num[i]) {
            dp[i+1]=min(dp[i+1],dp[i]);
            if(i+1<n && !num[i+1]) {
                dp[i+2]=min(dp[i+2],dp[i]+hei[i+1]-hei[i]);
            }
        } else {
            if(i+1<n) {
                dp[i+2]=min(dp[i+2],dp[i]+hei[i+1]-hei[i]);
                if(i+2<n) {
                    dp[i+3]=min(dp[i+3],dp[i]+hei[i+2]-hei[i]);
                }
            }
        }
    }
    cout<<dp[n]<<endl;
}