#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 pre()
{
cin >> n>>d;
vector<ll> arr(n);
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 = [&](int x, int l, int 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;
}
void solve() {
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
// pre();
int T = 1;
//cin >> T;
while (T--) {
solve();
}
}