#include <algorithm>
#include <functional>
#include <iostream>
#include <iomanip>
#include <vector>
#include <map>
#include <set>
#include <unordered_set>
#include <queue>
#include <numeric>
#include <bitset>
#include <cmath>
#include <random>
#include "list"

using namespace std;
using ll = long long;
using ull = unsigned long long;
//const ll mod = 998244353;
const ll mod = 1000000007;
const int inf = 1e9;
const ll linf = 1e18;
const int DX[] = {1, -1, 0, 0};
const int DY[] = {0, 0, 1, -1};


#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep_from(i, j, n) for (ll i = (j); i < (n); ++i)
#define rep_rev(i, n) for (ll i = n-1; i >= 0; --i)
#define rep_from_rev(i, j, n) for (ll i = n-1; i >= j; --i)
#define all(x) (x).begin(),(x).end()
#define sz(x) ll(x.size())

template<typename T>
inline T chmax(T &a, const T b) { return a = (a < b) ? b : a; }

template<typename T>
inline T chmin(T &a, const T b) { return a = (a > b) ? b : a; }

ll power(ll base, ll exponent) {
  if (exponent % 2) {
    return power(base, exponent - 1) * base % mod;
  } else if (exponent) {
    ll root_ans = power(base, exponent / 2);
    return root_ans * root_ans % mod;
  } else { return 1; }
}

ll inverse(ll x) { return power(x, mod - 2); }
ll gcd(ll a, ll b) {
  if (a < b) gcd(b, a);
  ll r;
  while (r = a % b) {
    a = b;
    b = r;
  }
  return b;
}

template<typename T>
ll sum(T begin, T end) { return accumulate(begin, end, 0ll); }

template<typename T>
struct combination {
    vector<ll> fact, inv;

    combination(int sz) : fact(sz + 1), inv(sz + 1) {
      fact[0] = 1;
      for (int i = 1; i <= sz; i++) { fact[i] = fact[i - 1] * i % mod; }
      inv[sz] = power(fact[sz], mod - 2);
      for (int i = sz - 1; i >= 0; i--) { inv[i] = inv[i + 1] * (i + 1) % mod; }
    }

    T C(int p, int q) const {
      if (q < 0 || p < q) return 0;
      return T(fact[p] * inv[q] % mod * inv[p - q] % mod);
    }

    T P(int p, int q) const {
      if(p < 0 || p < q) return 0;
      return T(fact[p] * inv[p - q] % mod);
    }
};

using Pair = pair<int, int>;
using LPair = pair<ll, ll>;

template<ll Modulus>
struct ModInt {
    ll a;

    constexpr ModInt(const ll x = 0) noexcept: a((x % mod + mod) % mod) {}

    constexpr ll &value() noexcept { return a; }

    constexpr const ll &value() const noexcept { return a; }

    constexpr ModInt operator+(const ModInt x) const noexcept {
      return ModInt(*this) += x;
    }

    constexpr ModInt operator-(const ModInt x) const noexcept {
      return ModInt(*this) -= x;
    }

    constexpr ModInt operator*(const ModInt x) const noexcept {
      return ModInt(*this) *= x;
    }

    constexpr ModInt operator/(const ModInt x) const noexcept {
      return ModInt(*this) /= x;
    }

    constexpr ModInt &operator+=(const ModInt x) noexcept {
      a += x.a;
      if (a >= Modulus) {
        a -= Modulus;
      }
      return *this;
    }

    constexpr ModInt &operator-=(const ModInt x) noexcept {
      if (a < x.a) {
        a += Modulus;
      }
      a -= x.a;
      return *this;
    }

    constexpr ModInt &operator*=(const ModInt x) noexcept {
      a = a * x.a % Modulus;
      return *this;
    }

    constexpr ModInt &operator/=(ModInt x) noexcept {
      ll exp = Modulus - 2;
      while (exp) {
        if (exp % 2) {
          *this *= x;
        }
        x *= x;
        exp /= 2;
      }
      return *this;
    }

    constexpr ModInt operator-() noexcept {
      return ModInt(-a);
    }

    friend ostream &operator<<(ostream &os, const ModInt &m) {
      os << m.a;
      return os;
    }
};

using mint = ModInt<mod>;

struct UnionFind {
    vector<int> par;
    vector<int> next;

    UnionFind(int n) : par(n, -1), next(n) {iota(all(next), 0);}

    int root(int x) {
      if (par[x] < 0)
        return x;
      return par[x] = root(par[x]);
    }

    void unite(int x, int y) {
      x = root(x);
      y = root(y);
      if (x == y)
        return;
      if (par[x] > par[y])
        swap(x, y);
      par[x] += par[y];
      par[y] = x;
      swap(next[x], next[y]);
    }

private:
    void unite_list(int x, int y) {

    }

    bool same(int x, int y) {
      int rx = root(x);
      int ry = root(y);
      return rx == ry;
    }
    int size(int x) { return -par[root(x)]; }
};

map<ll, int> primeFactorization(ll a) {
  map<ll, int> mp;
  for(ll i = 2; i * i <= a; i++) {
    while(a % i == 0) {
      mp[i]++;
      a /= i;
    }
  }
  if(a > 1) mp[a]++;
  return mp;
}

int main() {
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  ll n, k;
  cin >> n >> k;
  vector<int> p(n), c(n);
  rep(i, n) cin >> p[i];
  rep(i, n) cin >> c[i];
  rep(i, n) p[i]--;
  vector<int> used(n);
  vector<vector<int>> cyc;
  rep(i, n) {
    int x = i;
    if(used[x]) continue;
    vector<int> a;
    while(!used[x]) {
      used[x] = 1;
      a.push_back(x);
      x = p[x];
    }
    cyc.push_back(a);
  }
  ll ans = -linf;
  for(auto v: cyc) {
    vector<ll> cum(2*sz(v) + 1);
    rep(i, 2*sz(v)) cum[i+1] = cum[i] + c[v[i%sz(v)]];
    vector<ll> dp(2*sz(v)+1, -linf);
    rep(i, sz(v)) rep_from(j, i, 2*sz(v)) chmax(dp[j-i+1], cum[j+1] - cum[i]);
    rep_from(i, 1, sz(v)) chmax(dp[i+1], dp[i]);
    ll cnt = k / sz(v);
    ll loop = 0;
    for(int x: v) loop += c[x];
    chmax(ans, dp[min(sz(v), k)]);
    if(k > sz(v)) {
      chmax(ans, dp[min(sz(v), k)] + loop * (cnt - 1));
    }
    chmax(ans, dp[k % sz(v)] + loop * cnt);
  }
  cout << ans << endl;
}

Measured memory_bytes: 3840