#include <bits/stdc++.h>
#define ll long long
using namespace std;

int n, d;

void solve() {
    cin >> n >> d;
    vector<int> a(n), val(2 * n);
    for(auto &o : a) {
        cin >> o, val.push_back(o), val.push_back(2 * o);
    }
    sort(val.begin(), val.end());
    val.resize(unique(val.begin(), val.end()) - val.begin());
    auto get = [] (int l, int r, int x) {
        if(x < l) return l;
        else if(x > r) return r;
        else return x;
    };
    auto calc = [&](int l , int r) {
        ll sum = 0;
        int last = get(l, r, a[0]);
        for(int i = 1; i < n; i++) {
            sum += abs(last - get(l, r, a[i]));
            last = get(l, r, a[i]);
        }
        return sum;   
    };
    ll ans = 0;
    for(auto l : val) {
        ans = max(ans, calc(l, l + d));
    }
    cout << ans << '\n';
}


int main() {
    ios::sync_with_stdio(false);
    
    int t = 1;
    // cin >> t;
    while(t--) solve();

    return 0;
}