#include <bits/stdc++.h>
using namespace std;
using pint = pair<int, int>;
using pll = pair<long long, long long>;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

#define REP(i, n) for (long long i = 0; i < (long long)(n); ++i)
#define REP2(i, a, b) for (long long i = a; i < (long long)(b); ++i)
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, set<T> P)
{ for(auto it : P) { s << "" << it << " "; } return s; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) {  s << "{"; if (i > 0) { s << " "; } s << P[i] << "}, "; } return s; }
template<class T> ostream& operator << (ostream &s, deque<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }

template<class T> ostream& operator << (ostream &s, multiset<T> P)
{ for(auto it : P) { s << "<" << it << "> "; } return s; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ for(auto it : P) { s << "<" << it.first << "->" << it.second << "> "; } return s; }


/*///////////////////////////////////////////////////////*/
// Union-Find, modint, segtree, lazy segtree
/*///////////////////////////////////////////////////////*/

// 4-neighbor (or 8-neighbor)
const vector<int> dx = {1, 0, -1, 0, 1, -1, 1, -1};
const vector<int> dy = {0, 1, 0, -1, 1, 1, -1, -1};

// Union-Find
struct UnionFind {
    // core member
    vector<int> par;

    // constructor
    UnionFind() { }
    UnionFind(int n) : par(n, -1) { }
    void init(int n) { par.assign(n, -1); }
    
    // core methods
    int root(int x) {
        if (par[x] < 0) return x;
        else return par[x] = root(par[x]);
    }
    
    bool same(int x, int y) {
        return root(x) == root(y);
    }
    
    bool merge(int x, int y) {
        x = root(x), y = root(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y); // merge technique
        par[x] += par[y];
        par[y] = x;
        return true;
    }
    
    int size(int x) {
        return -par[root(x)];
    }
    
    // debug
    friend ostream& operator << (ostream &s, UnionFind uf) {
        map<int, vector<int>> groups;
        for (int i = 0; i < uf.par.size(); ++i) {
            int r = uf.root(i);
            groups[r].push_back(i);
        }
        for (const auto &it : groups) {
            s << "group: ";
            for (auto v : it.second) s << v << " ";
            s << endl;
        }
        return s;
    }
};

// modint
template<int MOD> struct Fp {
    // inner value
    long long val;
    
    // constructor
    constexpr Fp() noexcept : val(0) { }
    constexpr Fp(long long v) noexcept : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr long long get() const noexcept { return val; }
    constexpr int get_mod() const noexcept { return MOD; }
    
    // arithmetic operators
    constexpr Fp operator - () const noexcept {
        return val ? MOD - val : 0;
    }
    constexpr Fp operator + (const Fp &r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp &r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp &r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp &r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp &r) noexcept {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp &r) noexcept {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp& operator *= (const Fp &r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp& operator /= (const Fp &r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b, swap(a, b);
            u -= t * v, swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp pow(long long n) const noexcept {
        Fp res(1), mul(*this);
        while (n > 0) {
            if (n & 1) res *= mul;
            mul *= mul;
            n >>= 1;
        }
        return res;
    }
    constexpr Fp inv() const noexcept {
        Fp res(1), div(*this);
        return res / div;
    }

    // other operators
    constexpr bool operator == (const Fp &r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp &r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr istream& operator >> (istream &is, Fp<MOD> &x) noexcept {
        is >> x.val;
        x.val %= MOD;
        if (x.val < 0) x.val += MOD;
        return is;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<MOD> &x) noexcept {
        return os << x.val;
    }
    friend constexpr Fp<MOD> modpow(const Fp<MOD> &r, long long n) noexcept {
        return r.pow(n);
    }
    friend constexpr Fp<MOD> modinv(const Fp<MOD> &r) noexcept {
        return r.inv();
    }
};

// Binomial coefficient
template<class T> struct BiCoef {
    vector<T> fact_, inv_, finv_;
    constexpr BiCoef() {}
    constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
        init(n);
    }
    constexpr void init(int n) noexcept {
        fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
        int MOD = fact_[0].get_mod();
        for(int i = 2; i < n; i++){
            fact_[i] = fact_[i-1] * i;
            inv_[i] = -inv_[MOD%i] * (MOD/i);
            finv_[i] = finv_[i-1] * inv_[i];
        }
    }
    constexpr T com(int n, int k) const noexcept {
        if (n < k || n < 0 || k < 0) return 0;
        return fact_[n] * finv_[k] * finv_[n-k];
    }
    constexpr T fact(int n) const noexcept {
        if (n < 0) return 0;
        return fact_[n];
    }
    constexpr T inv(int n) const noexcept {
        if (n < 0) return 0;
        return inv_[n];
    }
    constexpr T finv(int n) const noexcept {
        if (n < 0) return 0;
        return finv_[n];
    }
};

// Segment Tree
template<class Monoid> struct SegTree {
    using Func = function<Monoid(Monoid, Monoid)>;

    // core member
    int SIZE;
    Func F;
    Monoid IDENTITY;
    
    // data
    int offset;
    vector<Monoid> dat;

    // constructor
    SegTree() {}
    SegTree(int n, const Func &f, const Monoid &identity)
    : SIZE(n), F(f), IDENTITY(identity) {
        offset = 1;
        while (offset < n) offset *= 2;
        dat.assign(offset * 2, IDENTITY);
    }
    void init(int n, const Func &f, const Monoid &identity) {
        SIZE = n;
        F = f;
        IDENTITY = identity;
        offset = 1;
        while (offset < n) offset *= 2;
        dat.assign(offset * 2, IDENTITY);
    }
    int size() const { return SIZE; }
    
    // set, a is 0-indexed //
    // build(): O(N)
    void set(int a, const Monoid &v) { dat[a + offset] = v; }
    void build() {
        for (int k = offset - 1; k > 0; --k)
            dat[k] = F(dat[k*2], dat[k*2+1]);
    }
    void build(const vector<Monoid> &vec) {
        for (int a = 0; a < vec.size() && a + offset < dat.size(); ++a)
            set(a, vec[a]);
        build();
    }
    
    // update a, a is 0-indexed, O(log N)
    void update(int a, const Monoid &v) {
        int k = a + offset;
        dat[k] = v;
        while (k >>= 1) dat[k] = F(dat[k*2], dat[k*2+1]);
    }
    
    // get [a, b), a and b are 0-indexed, O(log N)
    Monoid get(int a, int b) {
        Monoid vleft = IDENTITY, vright = IDENTITY;
        for (int left = a + offset, right = b + offset; left < right;
        left >>= 1, right >>= 1) {
            if (left & 1) vleft = F(vleft, dat[left++]);
            if (right & 1) vright = F(dat[--right], vright);
        }
        return F(vleft, vright);
    }
    Monoid get_all() { return dat[1]; }
    Monoid operator [] (int a) const { return dat[a + offset]; }
    
    // get max r that f(get(l, r)) = True (0-indexed), O(log N)
    // f(IDENTITY) need to be True
    int max_right(const function<bool(Monoid)> f, int l = 0) {
        if (l == SIZE) return SIZE;
        l += offset;
        Monoid sum = IDENTITY;
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(F(sum, dat[l]))) {
                while (l < offset) {
                    l = l * 2;
                    if (f(F(sum, dat[l]))) {
                        sum = F(sum, dat[l]);
                        ++l;
                    }
                }
                return l - offset;
            }
            sum = F(sum, dat[l]);
            ++l;
        } while ((l & -l) != l);  // stop if l = 2^e
        return SIZE;
    }

    // get min l that f(get(l, r)) = True (0-indexed), O(log N)
    // f(IDENTITY) need to be True
    int min_left(const function<bool(Monoid)> f, int r = -1) {
        if (r == 0) return 0;
        if (r == -1) r = SIZE;
        r += offset;
        Monoid sum = IDENTITY;
        do {
            --r;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(F(dat[r], sum))) {
                while (r < offset) {
                    r = r * 2 + 1;
                    if (f(F(dat[r], sum))) {
                        sum = F(dat[r], sum);
                        --r;
                    }
                }
                return r + 1 - offset;
            }
            sum = F(dat[r], sum);
        } while ((r & -r) != r);
        return 0;
    }
    
    // debug
    friend ostream& operator << (ostream &s, const SegTree &seg) {
        for (int i = 0; i < seg.size(); ++i) {
            s << seg[i];
            if (i != seg.size()-1) s << " ";
        }
        return s;
    }
};


vector<long long> calc_divisor(long long n) {
    vector<long long> res;
    for (long long i = 1LL; i*i <= n; ++i) {
        if (n % i == 0) {
            res.push_back(i);
            long long j = n / i;
            if (j != i) res.push_back(j);
        }
    }
    sort(res.begin(), res.end());
    return res;
}


template <class Abel> struct BIT {
    Abel UNITY_SUM = 0;
    vector<Abel> dat[2];

    // [0, n)
    BIT(int n, Abel unity = 0) : UNITY_SUM(unity) {
        init(n);
    }
    void init(int n) {
        for (int iter = 0; iter < 2; ++iter)
            dat[iter].assign(n + 1, UNITY_SUM);
    }
    
    // [a, b), a and b are 0-indexed
    inline void sub_add(int p, int a, Abel x) {
        for (int i = a; i < (int)dat[p].size(); i |= i + 1)
            dat[p][i] = dat[p][i] + x;
    }
    inline void add(int a, int b, Abel x) {
        sub_add(0, a, x * (-a));
        sub_add(1, a, x);
        sub_add(0, b, x * b);
        sub_add(1, b, x * (-1));
    }
    
    // [a, b), a and b are 0-indexed
    inline Abel sub_sum(int p, int a) {
        Abel res = UNITY_SUM;
        for (int i = a - 1; i >= 0; i = (i & (i + 1)) - 1)
            res = res + dat[p][i];
        return res;
    }
    inline Abel sum(int a, int b) {
        return sub_sum(0, b)
            + sub_sum(1, b) * b
            - sub_sum(0, a)
            - sub_sum(1, a) * a;
    }
    
    // debug
    void print() {
        for (int i = 0; i < (int)dat[0].size(); ++i)
            cout << sum(i, i + 1) << ",";
        cout << endl;
    }
};


struct HopcroftKarp {
    int sizeL, sizeR;
    vector<vector<int> > list; // left to right
    
    // result
    vector<bool> seen, matched;
    vector<int> level, matching;
    
    // base
    HopcroftKarp(int l, int r) : sizeL(l), sizeR(r), list(l, vector<int>()) { }
    inline vector<int>& operator [] (int i) { return list[i]; }
    inline void addedge(int from, int to) { list[from].push_back(to); }
    inline friend ostream& operator << (ostream& s, const HopcroftKarp& G) {
        s << endl;
        for (int i = 0; i < G.list.size(); ++i) {
            s << i << " : ";
            for (int j = 0; j < G.list[i].size(); ++j) {
                s << G.list[i][j];
                if (j + 1 != G.list[i].size()) s << ", ";
            }
            s << endl;
        }
        return s;
    }
    
    // methods
    void hobfs() {
        queue<int> que;
        for (int left = 0; left < sizeL; ++left) {
            level[left] = -1;
            if (!matched[left]) {
                que.push(left);
                level[left] = 0;
            }
        }
        level[sizeL] = sizeL;
        while (!que.empty()) {
            int left = que.front();
            que.pop();
            for (int i = 0; i < list[left].size(); ++i) {
                int right = list[left][i];
                int next = matching[right];
                if (level[next] == -1) {
                    level[next] = level[left] + 1;
                    que.push(next);
                }
            }
        }
    }
    bool hodfs(int left) {
        if (left == sizeL) return true;
        if (seen[left]) return false;
        seen[left] = true;
        for (int i = 0; i < list[left].size(); ++i) {
            int right = list[left][i];
            int next = matching[right];
            if (level[next] > level[left] && hodfs(next)) {
                matching[right] = left;
                return true;
            }
        }
        return false;
    }
    int solve() {
        seen.assign(sizeL, false);
        matched.assign(sizeL, false);
        level.assign(sizeL+1, -1);
        matching.assign(sizeR, sizeL);
        int res = 0;
        while (true) {
            hobfs();
            seen.assign(sizeL, false);
            bool finished = true;
            for (int left = 0; left < sizeL; ++left) {
                if (!matched[left] && hodfs(left)) {
                    matched[left] = true;
                    ++res;
                    finished = false;
                }
            }
            if (finished) break;
        }
        return res;
    }
};


/*
int main() {
    int N, M;
    cin >> N >> M;
    vector<long long> A(N), B(N), T(M), C(M);
    for (int i = 0; i < N; ++i) cin >> A[i];
    for (int i = 0; i < N; ++i) cin >> B[i];
    for (int j = 0; j < M; ++j) cin >> T[j] >> C[j];
    
    HopcroftKarp G(N, M);
    for (int i = 0; i < N; ++i)
}
*/
    

int main() {
    int N, K;
    cin >> N >> K;
    vector<long long> A(N*2), C(N*2);
    for (int i = 0; i < N; ++i) {
        cin >> A[i];
        A[i+N] = A[i];
    }
    for (int i = 0; i < N; ++i) {
        cin >> C[i];
        C[i+N] = C[i];
    }
    
    vector<long long> S(N*2+1, 0);
    for (int i = 0; i < N*2; ++i) S[i+1] = S[i] + A[i];
    
    long long res = 0;
    for (int l = 0; l < N; ++l) {
        
        //cout << "-----------=" << endl; COUT(l);
        
        vector<set<int>> st;
        for (int r = l; r < N*2 && r-l < N; ++r) {
            
            auto canmerge = [&](set<int> add) -> bool {
                set<int> se = st.back();
                bool ex = false;
                for (auto v : se) for (auto v2 : add) if (abs(v - v2) <= K) ex = true;
                return ex;
            };
            
            set<int> add;
            add.insert(C[r]);
            
            //COUT(canmerge(add));
            
            while (!st.empty() && canmerge(add)) {
                for (auto v : add) st.back().insert(v);
                add = st.back();
                st.pop_back();
            }
            st.push_back(add);
            
            //cout << r << ": " << st << endl;
            
            if (st.size() == 1) {
                res = max(res, S[r+1] - S[l]);
            }
        }
    }
    cout << res << endl;
}
    
    /*
    vector dp(N*2+1, vector(N*2+2, vector(52, false)));
    vector pl(N*2+1, vector(N*2+2, vector(52, -1)));
    for (int l = 0; l < N*2; ++l) {
        dp[l][l+1][C[l]] = true;
        pl[l][l+1][C[l]] = l;
    }
    
    for (int b = 2; b <= N; ++b) {
        for (int l = 0; l < N*2 && l+b <= N*2; ++l) {
            int r = l + b;
            
            for (int c = 0; c <= 50; ++c) {
                for (int m = l+1; m < r; ++m) {
                    if (!dp[l][m][c] && !dp[m][r][c]) continue;
                    
                    for (int c2 = max(0, c-K); c2 <= min(50, c+K); ++c2) {
                        if (dp[l][m][c] && dp[m][r][c2]) dp[l][r][c] = true;
                        if (dp[l][m][c2] && dp[m][r][c]) dp[l][r][c] = true;
                    }
                }
                
                //if (dp[l][r][c]) cout << l << ", " << r << ", " << c << endl;
            }
        }
    }
                  
    long long res = 0;
    for (int l = 0; l < N; ++l) {
        for (int r = l+1; r-l <= N && r <= N*2; ++r) {
            for (int c = 0; c <= 50; ++c) {
                if (dp[l][r][c]) {
                    
                    res = max(res, S[r] - S[l]);
                }
            }
        }
    }
    cout << res << endl;
    
     */