#include "bits/stdc++.h"
#include "bits/extc++.h"

using namespace std;
using namespace __gnu_pbds;

using ll = long long;
using ull = unsigned long long;

#define IOS ios::sync_with_stdio(0);cin.tie(0);
#define endl "\n"
#define hash gp_hash_table
#define yes cout<<"YES"<<endl;
#define no cout<<"NO"<<endl;
#define lowbit(x) x&(-x)
#define int ll
#define trees tree<int, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update>
const int mod = 998244353;

void solve() {
    int n, d;
    cin >> n >> d;
    set<int> s;
    vector<int> v(n + 1, 0);
    for (int i = 1; i <= n; i++) {
        cin >> v[i];
        s.insert(v[i]);
    }
    int k = -1;
//    for (auto i: s) {
//        int mins = i;
//        int maxs = i + d;
//        int ans = 0;
//        for (int j = 2; j <= n; j++) {
//            int a = min(max(mins, v[j]), maxs);
//            int b = min(max(mins, v[j - 1]), maxs);
//            ans += abs(a - b);
//        }
//        k = max(ans, k);
//    }
    for (auto i: s) {
        int mins = i - d;
        int maxs = i;
        int ans = 0;
        for (int j = 2; j <= n; j++) {
            int a = min(max(mins, v[j]), maxs);
            int b = min(max(mins, v[j - 1]), maxs);
            ans += abs(a - b);
        }
        k = max(ans, k);
    }
    cout << k << endl;


}


signed main() {

    IOS
    int t = 1;
//    cin >> t;
    while (t--)solve();
}