#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int,int> pi;
typedef pair<ll,ll> pl;
typedef pair<db,db> pd;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<db> vd;
typedef vector<str> vs;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<pd> vpd;
#define mp make_pair
#define f first
#define s second
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend()
#define rsz resize
#define ins insert
#define ft front()
#define bk back()
#define pf push_front
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)
const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18;
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1};
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count());
template<class T> bool ckmin(T& a, const T& b) {
return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) {
return a < b ? a = b, 1 : 0; }
int pct(int x) { return __builtin_popcount(x); }
int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x))
int cdiv(int a, int b) { return a/b+!(a<0||a%b == 0); } // division of a by b rounded up, assumes b > 0
int fstTrue(function<bool(int)> f, int lo, int hi) {
hi ++; assert(lo <= hi); // assuming f is increasing
while (lo < hi) { // find first index such that f is true
int mid = (lo+hi)/2;
f(mid) ? hi = mid : lo = mid+1;
}
return lo;
}
// INPUT
template<class A> void re(complex<A>& c);
template<class A, class B> void re(pair<A,B>& p);
template<class A> void re(vector<A>& v);
template<class A, size_t SZ> void re(array<A,SZ>& a);
template<class T> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
template<class H, class... T> void re(H& h, T&... t) { re(h); re(t...); }
template<class A> void re(complex<A>& c) { A a,b; re(a,b); c = {a,b}; }
template<class A, class B> void re(pair<A,B>& p) { re(p.f,p.s); }
template<class A> void re(vector<A>& x) { trav(a,x) re(a); }
template<class A, size_t SZ> void re(array<A,SZ>& x) { trav(a,x) re(a); }
// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(bool b) { return b ? "true" : "false"; }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
template<class A> str ts(complex<A> c) {
stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
str res = ""; F0R(i,SZ) res += char('0'+b[i]);
return res; }
template<class A, class B> str ts(pair<A,B> p);
template<class T> str ts(T v) { // containers with begin(), end()
bool fst = 1; str res = "{";
for (const auto& x: v) {
if (!fst) res += ", ";
fst = 0; res += ts(x);
}
res += "}"; return res;
}
template<class A, class B> str ts(pair<A,B> p) {
return "("+ts(p.f)+", "+ts(p.s)+")"; }
// OUTPUT
template<class A> void pr(A x) { cout << ts(x); }
template<class H, class... T> void pr(const H& h, const T&... t) {
pr(h); pr(t...); }
void ps() { pr("\n"); } // print w/ spaces
template<class H, class... T> void ps(const H& h, const T&... t) {
pr(h); if (sizeof...(t)) pr(" "); ps(t...); }
// DEBUG
void DBG() { cerr << "]" << endl; }
template<class H, class... T> void DBG(H h, T... t) {
cerr << ts(h); if (sizeof...(t)) cerr << ", ";
DBG(t...); }
#ifdef LOCAL // compile with -DLOCAL
#define dbg(...) cerr << "LINE(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif
// FILE I/O
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { ios_base::sync_with_stdio(0); cin.tie(0); }
void setIO(string s = "") {
unsyncIO();
// cin.exceptions(cin.failbit);
// throws exception when do smth illegal
// ex. try to read letter into int
if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}
/**
* Description: 1D point update, range query where \texttt{comb} is
* any associative operation. If $N=2^p$ then \texttt{seg[1]==query(0,N-1)}.
* Time: O(\log N)
* Source:
* http://codeforces.com/blog/entry/18051
* KACTL
* Verification: SPOJ Fenwick
*/
template<class T> struct Seg { // comb(ID,b) = b
const T ID = 0; T comb(T a, T b) { return max(a, b); }
int n; vector<T> seg;
void init(int _n) { n = _n; seg.assign(2*n,ID); }
void pull(int p) { seg[p] = comb(seg[2*p],seg[2*p+1]); }
void upd(int p, T val) { // set val at position p
seg[p += n] = val; for (p /= 2; p; p /= 2) pull(p); }
T query(int l, int r) { // sum on interval [l, r]
T ra = ID, rb = ID;
for (l += n, r += n+1; l < r; l /= 2, r /= 2) {
if (l&1) ra = comb(ra,seg[l++]);
if (r&1) rb = comb(seg[--r],rb);
}
return comb(ra,rb);
}
};
const int mx = 200005;
int n, x;
int t[mx];
Seg<int> mseg;
vi getvi(){
vi rval;
vi lens;
lens.pb(0);
for(int i = 0; i < n; i++){
//dbg(i, t[i]);
int lo = 0;
int hi = sz(lens)-1;
while(lo < hi){
int mid = (lo+hi)/2+1;
if(lens[mid] < t[i]){
lo = mid;
}
else hi = mid-1;
}
rval.pb(lo+1);
if(lo == sz(lens)-1){
lens.pb(t[i]);
}
else{
lens[lo+1] = t[i];
}
}
return rval;
}
int main() {
setIO();
cin >> n >> x;
for(int i = 0; i < n; i++){
cin >> t[i];
}
vi a = getvi();
vpi queries;
for(int i = 0; i < n; i++){
queries.pb(mp(t[i], i));
}
sort(queries.rbegin(), queries.rend());
for(int i = 0; i < n/2; i++){
swap(t[i], t[n-1-i]);
}
for(int i = 0; i < n; i++){
t[i] = -t[i];
}
vi b = getvi();
reverse(all(b));
for(int i = 0; i < n/2; i++){
swap(t[i], t[n-1-i]);
}
for(int i = 0; i < n; i++){
t[i] = -t[i];
}
//dbg(a, b);
vpi g;
for(int i = 0; i < n; i++){
g.pb(mp(t[i], i));
}
sort(g.rbegin(), g.rend());
// for(int i = 0; i < n; i++){
// dbg(i, t[i]);
// }
//dbg(queries, g);
mseg.init(n+5);
int gind = 0;
int ans = 0;
for(int i = 0; i < n; i++){
while(gind < sz(g)){
if(queries[i].f >= g[gind].f+x){
break;
}
int ind = g[gind].s;
mseg.upd(ind, b[ind]);
gind++;
}
int ind = queries[i].s;
ckmax(ans, a[ind]+mseg.query(ind+1, n+1));
}
ps(ans);
// you should actually read the stuff at the bottom
}
/* stuff you should look for
* int overflow, array bounds
* special cases (n=1?)
* do smth instead of nothing and stay organized
* WRITE STUFF DOWN
*/
