#include "bits/stdc++.h"

// Begin Header {{{
#pragma region
using namespace std;
using imax = intmax_t;
using usize = size_t;
using ld = long double;

#ifndef DEBUG
#define dump(...)
#endif

#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define rep(i, b, e) for (intmax_t i = (b), i##_limit = (e); i < i##_limit; ++i)
#define repc(i, b, e) for (intmax_t i = (b), i##_limit = (e); i <= i##_limit; ++i)
#define repr(i, b, e) for (intmax_t i = (b), i##_limit = (e); i >= i##_limit; --i)
#define var(Type, ...) Type __VA_ARGS__; input(__VA_ARGS__)
#define let const auto

constexpr size_t    operator""_zu(unsigned long long value) { return value; };
constexpr intmax_t  operator""_jd(unsigned long long value) { return value; };
constexpr uintmax_t operator""_ju(unsigned long long value) { return value; };

constexpr int INF = 0x3f3f3f3f;
constexpr intmax_t LINF = 0x3f3f3f3f3f3f3f3f_jd;

template <class T, class Compare = less<>>
using MaxHeap = priority_queue<T, vector<T>, Compare>;
template <class T, class Compare = greater<>>
using MinHeap = priority_queue<T, vector<T>, Compare>;

inline void input() {}
template <class Head, class... Tail>
inline void input(Head&& head, Tail&&... tail) {
    cin >> head;
    input(forward<Tail>(tail)...);
}

template <class Container, class Value = typename Container::value_type,
            enable_if_t<!is_same<Container, string>::value, nullptr_t> = nullptr>
inline istream& operator>>(istream &is, Container &vs) {
    for (auto &v: vs) is >> v;
    return is;
}

inline void output() { cout << "\n"; }
template <class Head, class... Tail>
inline void output(Head&& head, Tail&&... tail) {
    cout << head;
    if (sizeof...(tail)) cout << " ";
    output(forward<Tail>(tail)...);
}

template <class Container, class Value = typename Container::value_type,
            enable_if_t<!is_same<Container, string>::value, nullptr_t> = nullptr>
inline ostream& operator<<(ostream &os, const Container &vs) {
    static constexpr const char *delim[] = {" ", ""};
    for (auto it = begin(vs); it != end(vs); ++it) {
        os << delim[it == begin(vs)] << *it;
    }
    return os;
}

template <class Iterator>
inline void join(const Iterator &Begin, const Iterator &End, const string &delim = "\n", const string &last = "\n") {
    for (auto it = Begin; it != End; ++it) {
        cout << ((it == Begin) ? "" : delim) << *it;
    }
    cout << last;
}

template <class T>
inline vector<T> makeVector(const T &initValue, size_t sz) {
    return vector<T>(sz, initValue);
}

template <class T, class... Args>
inline auto makeVector(const T &initValue, size_t sz, Args... args) {
    return vector<decltype(makeVector<T>(initValue, args...))>(sz, makeVector<T>(initValue, args...));
}

template <class Func>
class FixPoint : Func {
public:
    explicit constexpr FixPoint(Func&& f) noexcept : Func(forward<Func>(f)) {}

    template <class... Args>
    constexpr decltype(auto) operator()(Args&&... args) const {
        return Func::operator()(*this, std::forward<Args>(args)...);
    }
};

template <class Func>
static inline constexpr decltype(auto) makeFixPoint(Func&& f) noexcept {
    return FixPoint<Func>{forward<Func>(f)};
}

template <class Container>
struct reverse_t {
    Container &c;
    reverse_t(Container &c) : c(c) {}
    auto begin() { return c.rbegin(); }
    auto end() { return c.rend(); }
};

template <class Container>
auto reversed(Container &c) {
    return reverse_t<Container>(c);
}

template <class T>
inline bool chmax(T &a, const T &b) noexcept {
    return b > a && (a = b, true);
}

template <class T>
inline bool chmin(T &a, const T &b) noexcept {
    return b < a && (a = b, true);
}

template <class T>
inline T diff(const T &a, const T &b) noexcept {
    return a < b ? b - a : a - b;
}

void ioinit() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << fixed << setprecision(10);
    clog << fixed << setprecision(10);
}
#pragma endregion
// }}} End Header

signed main() {
    ioinit();

    var(usize, N, K);

    vector<usize> P(N);
    for (auto &Pi: P) cin >> Pi, Pi--;
    vector<imax> C(N);
    input(C);

    // {mu, mu_sum, lamda, lamda_sum}
    const auto detectCycle = [&](const usize& s) -> tuple<imax, imax, imax, imax> {
        usize tortoise = s;
        usize hare = s;
        do {
            tortoise = P[tortoise];
            hare = P[P[hare]];
        } while (tortoise != hare);

        tortoise = s;
        imax mu = 0;
        imax mu_sum = 0;
        while (tortoise != hare) {
            mu++;
            mu_sum += C[P[tortoise]];
            tortoise = P[tortoise];
            hare = P[hare];
        }
        assert(mu == 0 && mu_sum == 0);

        imax lamda = 0;
        imax lamda_sum = 0;
        do {
            lamda++;
            lamda_sum += C[P[hare]];
            hare = P[hare];
        } while (hare != tortoise);

        return {mu, mu_sum, lamda, lamda_sum};
    };

    imax res = -LINF;
    rep(s, 0, N) {
        const auto [mu, mu_sum, lamda, lamda_sum] = detectCycle(s);
        // mu == 0 && mu_sum == 0
        dump(s, mu, mu_sum, lamda, lamda_sum);
        if (lamda_sum > 0) {
            imax k = K;
            imax sum = lamda_sum * (k / lamda);
            k %= lamda;
            if (k == 0) {
                k += lamda;
                sum -= lamda_sum;
            }
            imax maxv = sum;
            usize cur = s;
            rep(_, 0, k) {
                sum += C[P[cur]];
                chmax(maxv, sum);
                cur = P[cur];
            }
            chmax(res, maxv);
        } else {
            imax sum = 0, maxv = -LINF;
            usize cur = s;
            rep(_, 0, min<imax>(K, lamda)) {
                sum += C[P[cur]];
                chmax(maxv, sum);
                cur = P[cur];
            }
            chmax(res, maxv);
        }
    }

    output(res);
    return 0;
}

Measured memory_bytes: 3708