// yukicoder: 838 Noelちゃんと星々3
// 2019.9.7 bal4u

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef long long ll;

//// 高速入力
#if 1
int getchar_unlocked(void);
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif

int in() {  // 整数の入力（負数対応）
	int n = 0, c = gc();
	if (c == '-') {	c = gc();
		do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int y[100005]; int N;
int dp[100005];

void Qsort(int *a, int l, int r) {
	int i, j, m, t;
	
	i = l, j = r, m = a[(l+r) >> 1];
	while (1) {
		while (a[i] < m) i++;
		while (m < a[j]) j--;
		if (i >= j)	break;
		t = a[i], a[i] = a[j], a[j] = t;
		i++, j--;
	}
	if (l+1 < i) Qsort(a, l, i-1);
	if (j+1 < r) Qsort(a, j+1, r);
}

inline static int MIN(int a, int b) { return a < b? a: b; }

int main()
{
	int i;
	
	N = in();
	for (i = 0; i < N; i++) y[i] = in();
	Qsort(y, 0, N-1);
	dp[0] = y[N-1]+1, dp[1] = y[1]-y[0], dp[2] = y[2]-y[0];
	for (i = 3; i < N; i++)
		dp[i] = MIN(dp[i-2]+y[i]-y[i-1], dp[i-3]+y[i]-y[i-2]);
	printf("%d\n", dp[N-1]);
	return 0;
}