#include "bits/stdc++.h"
// Custom Header <<<
#define ALL(x) x.begin(), x.end()
#define rep(i, s, n)      for(int i(s); i < int(n); ++i)
#define endl '\n'
#ifndef YDK
#define eprintf(...)
#endif
using namespace std;
using i64 = long long;
using pii = pair<int, int>;
template<class A, class B>inline bool chmax(A &a, const B &b){return b>a ? a=b,1 : 0;}
template<class A, class B>inline bool chmin(A &a, const B &b){return b<a ? a=b,1 : 0;}
constexpr int INF  = 0x3f3f3f3f;
constexpr i64 LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr int MOD  = int(1e9) + 7;
// >>>

signed main()
{
    int N;
    int a[100010];

    cin >> N;
    rep(i, 0, N) cin >> a[i];

    sort(a, a+N);

    i64 dp[100010];
    dp[0] = LINF;
    dp[1] = a[1] - a[0];
    if (2 < N) dp[2] = a[2] - a[0];

    for (int i = 3; i < N; ++i) {
        dp[i] = min(
                dp[i-2] + (a[i] - a[i-1]),
                dp[i-3] + (a[i] - a[i-2]));
    }

    cout << (dp[N-1]) << endl;

    return 0;
}

/* vim:set foldmethod=marker foldmarker=<<<,>>> : */