#include <bits/stdc++.h>

#define maxn 10005
#define int long long

using namespace std;

int n, d;
int a[maxn];
int b[maxn];

int tot;
int w[maxn];

signed main() {
	scanf("%lld%lld", &n, &d);
	for (int i = 1; i <= n; i++) scanf("%lld", &a[i]);
	for (int i = 1; i <= n; i++) {
		w[++tot] = a[i];
		w[++tot] = a[i] - d;
	}
	int ans = 0;
	for (int p = 1; p <= tot; p++) {
		int l = w[p], r = l + d;
//		cout<<l<<" "<<r<<endl;
		for (int i = 1; i < n; i++) {
			b[i] = max(a[i], l);
			b[i] = min(b[i], r);
		}
		int res = 0;
		for (int i = 1; i < n; i++) res += abs(b[i] - b[i + 1]);
		ans = max(ans, res);
	}
	printf("%lld\n", ans);
	return 0;
}