#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Edge = int;
using Graph = vector<vector<Edge>>;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
const ll MOD = 1000000007;
const ll nmax = 8;
const ll INF = LLONG_MAX - 1000000;
const int MAX = 510000;
bool graph[nmax][nmax];
long long fac[MAX], finv[MAX], inv[MAX];

void COMinit()
{
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++)
    {
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

ll COM(int n, int k)
{
    if (n < k)
        return 0;
    if (n < 0 || k < 0)
        return 0;

    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

vector<vector<ll>> dist = vector<vector<ll>>(nmax, vector<ll>(nmax, INF));
struct SegmentTree
{
private:
    ll n;
    vector<ll> node;

public:
    SegmentTree(vector<ll> v)
    {
        ll sz = v.size();
        n = 1;
        while (n < sz)
        {
            n *= 2;
        }
        node.resize(2 * n - 1, INF);

        for (ll i = 0; i < sz; i++)
        {
            node[i + n - 1] = v[i];
        }

        for (ll i = n - 2; i >= 0; i--)
        {
            node[i] = min(node[2 * i + 1], node[2 * i + 2]);
        }
    }
    void update(ll x, ll val)
    {
        x += (n - 1);
        node[x] = val;
        while (x > 0)
        {
            x = (x - 1) / 2;
            node[x] = min(node[2 * x + 1], node[2 * x + 2]);
        }
    }

    // findは半開区間で考える
    ll find(ll a, ll b, ll k = 0, ll l = 0, ll r = -1)
    {
        if (r < 0)
            r = n;

        if (r <= a || b <= l)
            return INF;

        if (a <= l && r <= b)
            return node[k];

        ll vl = find(a, b, 2 * k + 1, l, (l + r) / 2);
        ll vr = find(a, b, 2 * k + 2, (l + r) / 2, r);
        return min(vl, vr);
    }
};
void warshall_floyd(ll n)
{
    for (size_t i = 0; i < n; i++)
    {
        for (size_t j = 0; j < n; j++)
        {
            for (size_t k = 0; k < n; k++)
            {
                dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
            }
        }
    }
}

class UnionFind
{
public:
    vector<ll> Parent;

    UnionFind(ll N)
    {
        Parent = vector<ll>(N, -1);
    }
    ll find(ll A)
    {
        if (Parent[A] < 0)
            return A;
        return Parent[A] = find(Parent[A]);
    }

    ll size(ll A)
    {
        return -Parent[find(A)];
    }

    bool Union(ll A, ll B)
    {
        A = find(A);
        B = find(B);
        if (A == B)
        {
            return false;
        }
        if (size(A) < size(B))
            swap(A, B);

        Parent[A] += Parent[B];
        Parent[B] = A;

        return true;
    }
};

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b)
{
    ll g = gcd(a, b);
    return a / g * b;
}

ll mulMod(ll a, ll b)
{
    return (((a % MOD) * (b % MOD)) % MOD);
}

ll powMod(ll a, ll p)
{
    if (p == 0)
    {
        return 1;
    }
    else if (p % 2 == 0)
    {
        ll half = powMod(a, p / 2);
        return mulMod(half, half);
    }
    else
    {
        return mulMod(powMod(a, p - 1), a);
    }
}

ll ceil(ll a, ll b)
{
    return (a + b - 1) / b;
}

vector<ll> tsort(Graph G)
{
    ll N = G.size();
    vector<ll> in(N);
    for (auto &&edges : G)
    {
        for (auto &&edge : edges)
        {
            in[edge]++;
        }
    }

    queue<int> que;

    for (int i = 0; i < N; i++)
    {
        if (in[i] == 0)
        {
            que.push(i);
        }
    }
    int cnt = 0;
    vector<ll> ans;
    while (!que.empty())
    {
        int v = que.front();
        que.pop();
        ans.push_back(v);
        for (auto &&next : G[v])
        {

            in[next]--;
            if (in[next] == 0)
            {
                que.push(next);
            }
        }
    }
    return ans;
}

ll score[5010][5010];
void solve(long long N, long long K, std::vector<long long> P, std::vector<long long> C)
{
    vector<vector<ll>> loop;
    vector<bool> seen(N, false);
    vector<ll> l;
    for (int i = 0; i < N; i++)
    {
        l.clear();
        if (seen[i])
            continue;

        ll now = i;
        seen[now] = true;
        l.push_back(now);
        while (!seen[P[now]])
        {
            now = P[now];
            seen[now] = true;
            l.push_back(now);
        }

        loop.push_back(l);
    }
    ll ans = -INF;
    for (auto &&v : loop)
    {
        for (auto &&start : v)
        {
            ll now = start;
            for (int i = 0; i < v.size(); i++)
            {
                score[i + 1][start] = score[i][start] + C[P[now]];
                now = P[now];
            }
        }

        // for (auto &&start : v)
        // {
        //     for (int i = 0; i < v.size(); i++)
        //     {
        //         cout << score[i+1][start] << " ";
        //     }
        //     cout << endl;
        // }
        if (K <= v.size())
        {
            // 今あるスコアの最大値
            for (auto &&start : v)
            {
                for (int i = 0; i < K; i++)
                {
                    ans = max(ans, score[i + 1][start]);
                }
            }
        }
        else
        {
            if (score[v.size()][v[0]] < 0)
            {
                // 今あるスコアの最大値
                for (auto &&start : v)
                {
                    for (int i = 0; i < v.size(); i++)
                    {
                        ans = max(ans, score[i + 1][start]);
                    }
                }
            }
            else
            {
                ll loops = K / v.size();
                ll base = loops * score[v.size()][v[0]];
                ans = max(ans, base);
                if (K % v.size() == 0)
                {
                    base = (loops -1) * score[v.size()][v[0]]; 
                    // 今あるスコアの最大値
                    for (auto &&start : v)
                    {
                        for (int i = 0; i < v.size(); i++)
                        {
                            ans = max(ans, score[i + 1][start] + base);
                        }
                    }
                }
                else
                {
                    // 今あるスコアの最大値
                    for (auto &&start : v)
                    {
                        for (int i = 0; i < K % v.size(); i++)
                        {
                            ans = max(ans, score[i + 1][start] + base);
                        }
                    }
                }
            }
        }
    }
    cout << ans << endl;
}

int main()
{
    long long N;
    scanf("%lld", &N);
    long long K;
    scanf("%lld", &K);
    std::vector<long long> P(N);
    for (int i = 0; i < N; i++)
    {
        ll p;
        cin >> p;
        --p;
        P[i] = p;
    }
    std::vector<long long> C(N);
    for (int i = 0; i < N; i++)
    {
        scanf("%lld", &C[i]);
    }
    solve(N, K, std::move(P), std::move(C));
    return 0;
}


Measured memory_bytes: 199588