#include<cstdio>
#include<iostream>
#include<cmath>
using namespace std;
const int o=5010;
int n,d,a[o],b[o],ans;
inline void slv(int l){
	for(int i=1,r=l+d;i<=n;++i) b[i]=max(l,min(a[i],r));
	int res=0;
	for(int i=1;i<n;++i) res+=abs(b[i]-b[i+1]);
	ans=max(ans,res);
}
int main(){
	scanf("%d%d",&n,&d);
	for(int i=1;i<=n;++i) scanf("%d",&a[i]);
	for(int i=1;i<=n;++i) slv(a[i]),slv(a[i]-d);
	printf("%d",ans);
	return 0;
}