#include <bits/stdc++.h>

void solve() {
    int n, d;
    std::cin >> n >> d;
    std::vector<int> a(n);
    for (int i = 0; i < n; ++i) {
        std::cin >> a[i];
    }
    std::set<int> st(a.begin(), a.end());
    auto func = [&](int l, int r) ->int64_t {
        std::vector<int> v = a;
        for(int i = 0; i < n; ++i) {
            v[i] = std::max(v[i], l);
            v[i] = std::min(v[i], r);
        }
        int64_t res = 0;
        for(int i = 0; i + 1 < n; ++i) {
            res += std::abs(v[i] - v[i + 1]);
        }
        return res;
    };
    int64_t ans = 0;
    int64_t lst = -1E9;
    for(const auto &x : st) {
        int64_t l = lst, r = x, res = 0;
        while(l <= r) {
            int64_t lmid = l + (r - l + 1) / 3;
            int64_t rmid = r - (r - l + 1) / 3;
            int64_t lres = func(lmid, lmid + d);
            int64_t rres = func(rmid, rmid + d);
            if(lres > rres) {
                r = rmid - 1;
                res = std::max(res, lres);
            } else {
                l = lmid + 1;
                res = std::max(res, rres);
            }
        }
        ans = std::max(ans, res);
        lst = x;
    }
    std::cout << ans << '\n';
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int T = 1;
    while(T--) {
        solve();
    }
    return 0;
}