#include<bits/stdc++.h>  
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N = 5e6 + 5;
ll n, b, k, m,d;
ll mod = 1e9 + 9;
//ll d[10000005]{},cnt=0;
bool vis[10000005]{};
vector<int> prime;
void solve() {
    cin >> n >> d;
    vector<ll> arr(n);
    for (auto i : arr) cin >> arr[i];
    ll ans = 0;
    for (int i = 0; i < n; i++)
    {
        ll l = arr[i], r = arr[i];
        for (int i = 1; i < n; i++)
        {
            auto turn = [&](ll x, ll l, ll r)
                {
                    if (x > r) return r;
                    else if (x < l) return l;
                    else return x;
                };
            ans = max({ ans,(ll)abs(turn(arr[i],l,l + d) - turn(arr[i - 1],l,l + d)),(ll)abs(turn(arr[i],r,r - d) - turn(arr[i - 1],r,r - d)) });
        }
    }
    cout << ans << endl;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
   // pre();
    int T = 1;
    //cin >> T;
    while (T--) {
        solve();
    }
}