#include <bits/stdc++.h>
using namespace std;
#define int long long
#define mp make_pair
#define inf 1e18
#define pii pair <int, int>
const int mod = 1e9 + 7;
inline int read () {
	int x = 0, f = 1;
	char ch = getchar ();
	while (ch < '0' || ch > '9') f = ((ch == '-') ? -1 : f), ch = getchar ();
	while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar ();
	return x * f;
}
inline void write (int x) {
	if (x < 0) x = -x, putchar ('-');
	if (x >= 10) write (x / 10);
	putchar (x % 10 + '0');
}
inline int quickmod (int x, int y) {
	int Ans = 1;
	while (y) {
		if (y & 1) Ans = (Ans * x) % mod;
		x = (x * x) % mod;
		y >>= 1;
	}
	return Ans;
}
inline int Abs(int x) {
	if(x > 0) return x;
	return -x;
}
inline void Mn(int &x, int y) {
	if(x > y) x = y;
}
int n, m;
int a[5005], b[5005];
inline int rng(int l, int r, int x) {
	l = a[l], r = a[r];
	if(l > r) swap(l, r);
	return l <= x && x <= r;
}
int pathl(int l, int h, int r, int H) {
	if(l == r) return 1;
	if(l < r) return a[r] == H;
	return a[l] == h;
}
int pathr(int l, int h, int r, int H) {
	if(l == r) return 1;
	if(l < r) return a[l] == h;
	return a[r] == H;
}
struct Node {
	int i, j, k, e;
	Node() {}
	Node(int A, int B, int C, int D) {
		i = A, j = B, k = C, e = D;
	}
	bool operator <(const Node &A) const {
		return e > A.e;
	}
};
int f[5005][5005][2];
bool vis[5005][5005][2];
signed main () {
//	freopen (".in", "r", stdin);
//	freopen (".out", "w", stdout);
	n = read();
	for(int i = 1; i <= n; i++) a[i] = read();
	b[++m] = a[1];
	for(int i = 2; i < n; i++) if((a[i-1] < a[i]) ^ (a[i] < a[i+1])) b[++m] = a[i];
	b[++m] = a[n];
	swap(a, b), swap(n, m);
	memset(f, 0x3f, sizeof f);
	priority_queue <Node> Q;
	f[1][n][0] = 0, Q.push(Node(1, n, 0, 0));
	while(!Q.empty()) {
		Node now = Q.top();
		Q.pop();
		int i = now.i, j = now.j, k = now.k;
		
		if(i >= j) return printf("%lld\n", f[i][j][k]) & 0;
		if(vis[i][j][k]) continue;
		vis[i][j][k] = 1;
		int h = (!k ? a[i] : a[j]);
		for(auto I : {i - 1, i, i + 1}) {
			for(auto J : {j - 1, j, j + 1}) {
				for(auto K : {0, 1}) {
					int H = (!K ? a[I] : a[J]), val = Abs(H - h);
					
					if(!rng(I, I + 1, H) || !rng(J - 1, J, H) || I < 1 || I > n || J < 1 || J > n) continue;
					
					if(!pathl(i, h, I, H)) continue;
//					if(i == 3 && j == 7 && k == 0 && I == 3 && J == 6 && K == 1) printf("--\n");
					if(!pathr(j, h, J, H)) continue;
					
					if(f[I][J][K] > f[i][j][k] + val) {
						f[I][J][K] = f[i][j][k] + val;
						Q.push(Node(I, J, K, f[I][J][K]));
					}
				}
			}
		}
	}
//	printf("vis:%lld\n", (int)vis[3][7][0]);
//	printf("vis:%lld\n", (int)vis[3][6][1]);
	return 0;
}
/*
7
0 10 1 20 5 10 0
*/