#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define F first
#define S second
signed main(){
    int n , d;
    cin >> n >> d;
    vector<int> a(n);
    for(auto &i : a) cin >> i;
    int ans = 0;
    auto check = [&](int l, int r){
    	auto v = a;
    	for(auto &i : v){
    		if(i < l) i = l;
    		else if(i > r) i = r;
		}
		int sum = 0;
		for(int i = 1; i < n; i++){
			sum += abs(v[i] - v[i - 1]);
		}
        ans = max(ans, sum);
	};
    for(int it : a){
    	for(int i = -3; i <= 2; i++){
    		  check(it - i, it - i + d);
    		  check(it + i - d, it + i);
		}
	}
	
	cout << ans << '\n';
    
}