#include <bits/stdc++.h>
using namespace std;

// template {{{
#define  range(i, l, r) for (int i = (int)(l); i < (int)(r); (i) += 1)
#define rrange(i, l, r) for (int i = (int)(r) - 1; i >= (int)(l); (i) -= 1)

#define  whole(f, x, ...) ([&](decltype((x)) container) { return (f)(  begin(container),  end(container), ## __VA_ARGS__); })(x)
#define rwhole(f, x, ...) ([&](decltype((x)) container) { return (f)( rbegin(container), rend(container), ## __VA_ARGS__); })(x)

#define debug(x) cerr << "(" << __LINE__ << ")" << #x << ": " << (x) << endl

using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;

// constexpr i32 mod   = 998244353;
constexpr i32 mod   = 1e9 + 7;
constexpr i32 inf   = 1001001001;
constexpr i64 infll = 1001001001001001001ll;

constexpr int dx[] = {0, -1, 1, 0, -1, 1, -1, 1};
constexpr int dy[] = {-1, 0, 0, 1, -1, -1, 1, 1};

struct IoSetup { IoSetup(int x = 15){ cin.tie(0); ios::sync_with_stdio(0); cout << fixed << setprecision(x); cerr << fixed << setprecision(x); } } iosetup;

template <typename T = i64> T input() { T x; cin >> x; return x; }

template <typename T> ostream &operator<<(ostream &os, vector<T> &v) { range(i, 0, v.size()) { os << v[i] << (i + 1 != v.size() ? " " : ""); } return os; }
template <typename T> istream &operator>>(istream &is, vector<T> &v) { for (T &in : v) is >> in; return is; }

template <typename T1, typename T2> ostream &operator<<(ostream &os, pair<T1, T2> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
template <typename T1, typename T2> istream &operator>>(istream &is, pair<T1, T2> &p) { is >> p.first >> p.second; return is; }

template <typename T> vector<T> make_vector(size_t a, T b) { return vector<T>(a, b); }
template <typename... Ts> auto make_vector(size_t a, Ts... ts) { return vector<decltype(make_vector(ts...))>(a, make_vector(ts...)); }

template <typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }
template <typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }
// }}}


// union find {{{
class union_find {

    using data_type = int_fast32_t;
    std::vector< data_type > data_;

    public:
    union_find(std::size_t size) : data_(size, -1) {}

    std::size_t size() const {
        return data_.size();
    }

    data_type get_root(data_type x) {
        return (data_[x] < 0 ? x : data_[x] = get_root(data_[x]));
    }

    bool is_root(data_type x) {
        return x == get_root(x);
    }

    bool is_same(data_type x, data_type y) {
        return get_root(x) == get_root(y);
    }

    void unite(data_type x, data_type y) {
        x = get_root(x); y = get_root(y);
        if (x == y) return;

        if (data_[x] > data_[y]) std::swap(x, y);
        data_[x] += data_[y];
        data_[y] = x;
    }

    data_type element_count(data_type x) {
        return -data_[get_root(x)];
    }
};
// }}}

void solver() {
    i64 n = input(), K = input();
    vector< int > ps(n);
    vector< i64 > cs(n);

    cin >> ps >> cs;

    for (auto &p: ps) p--;

    i64 ans = -infll;

    union_find uf(n);
    vector< bool > used(n);
    range(i, 0, n) {
        if (used[i]) continue;
        for (int j = ps[i]; j != i; j = ps[j]) {
            uf.unite(j, i);
            used[j] = true;
        }
    }

    range(i, 0, n) {
        i64 k = K;
        // debug(i);
        i64 sz = uf.element_count(i);
        vector< i64 > score(sz + 1);
        int v = i;
        range(j, 1, sz + 1) {
            v = ps[v];
            score[j] = score[j - 1] + cs[v]; 
        }

        // debug(score);

        i64 sum = 0;
        if (score[sz] > 0) {
            // debug(score[sz]);
            sum += score[sz] * (k / sz);
            k %= sz;

            if (k == 0) {
                k = sz;
                sum -= score[sz];
            }

            i64 max_s = -infll;
            range(j, 1, k + 1) {
                chmax(max_s, score[j]);
            }

            chmax(ans, sum + max_s);
            // debug(sum);
            // debug(max_s);
        } else {
            i64 max_s = -infll;
            range(j, 1, min(sz, k) + 1) {
                chmax(max_s, score[j]);
            }

            chmax(ans, max_s);
            // debug(max_s);
        }
    }

    cout << ans << endl;
}

signed main(int argc, char *argv[]) {
    solver();
}


Measured memory_bytes: 3692