#include <bits/stdc++.h>
using namespace std;
#define repi(i,a,b) for(long long i = (long long)(a); i < (long long)(b); i++)
using ll = long long; 

auto f = [](ll x, ll y, bool b) { return max(0ll, (b ? 1 : -1) * (y - x)); };
auto min3 = [](ll a, ll b, ll c) { return min(a, min(b, c)); };
int main(void) {
    ll n, p; cin >> n >> p;
    assert(n >= 2);
    assert(n <= 200000);
    assert(p >= 0);
    assert(p <= 1e9);
    ll a0, a1; cin >> a0 >> a1;
    assert(a0 >= 0);
    assert(a0 <= 1e9);
    assert(a1 >= 0);
    assert(a1 <= 1e9);
    ll w = p, r = f(a0, a1, true), l = f(a0, a1, false) + p;
    ll pw, pr, pl;
    repi(i, 1, n-1) {
        a0 = a1; cin >> a1;
        assert(a1 >= 0);
        assert(a1 <= 1e9);
        swap(w, pw); swap(l, pl); swap(r, pr);
        w = p + min3(pw, pr, pl);
        r = min(p, f(a0, a1, true )) + min(pw, pr);
        l = min(p, f(a0, a1, false)) + min(pw, pl);
    }
    cout << min3(w, r, l) << endl;
    return 0;
}