#ifdef LOCAL
    #define _GLIBCXX_DEBUG
    #define __clock__
#else
    #pragma GCC optimize("Ofast")
#endif
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\n'; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<'\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define SZ(x) ((ll)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define MP make_pair
#define p_yes() p("YES")
#define p_no() p("NO")

ll SUM(VI& V){
  return accumulate(ALL(V), 0LL);
}

ll MIN(VI& V){return *min_element(ALL(V));}
ll MAX(VI& V){return *max_element(ALL(V));}

void print_vector(VI& V){
  ll n = V.size();
  rep(i, n){
    if(i) cout << ' ';
    cout << V[i];
  }
  cout << endl;
}

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;
}

// long double
using ld = long double;
#define EPS (1e-14)
#define equals(a,b) (fabs((a)-(b)) < EPS)

void no(){p_no(); exit(0);}
void yes(){p_yes(); exit(0);}

const ll mod = 1e9 + 7;
const ll inf = 1e18;
const double PI = acos(-1);

// snuke's mint
// auto mod int
// https://youtu.be/L8grWxBlIZ4?t=9858
// https://youtu.be/ERZuLAxZffQ?t=4807 : optimize
// https://youtu.be/8uowVvQ_-Mo?t=1329 : division
// const int mod = 1000000007;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res+=a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res-=a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res*=a;
  }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const {
    return pow(mod-2);
  }
  mint& operator/=(const mint a) {
    return (*this) *= a.inv();
  }
  mint operator/(const mint a) const {
    mint res(*this);
    return res/=a;
  }
};

// for codeforces
void solve(){
  ll N;
  cin>>N;
  VI A(N);
  rep(i, N){
    cin >> A[i];
  }
}

struct AccSum{
    vector<ll> Ac;
    ll L;
    AccSum(){}
    AccSum(vector<ll> &A){
        L = A.size();
        Ac.resize(L+1);
        FOR(i, 0, L){
            Ac[i+1] = Ac[i] + A[i];
        }
    }
    // sum of [a, b]
    ll sum(ll a, ll b){
        if(a<0) return -1;
        if(b>L-1) return -1;
        return Ac[b+1] - Ac[a];
    }
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N,K;
    cin>>N>>K;
    debug(N,K);

    VI P(N);
    rep(i, N){
      cin >> P[i];
      P[i]--;
    }

    VI C(N);
    rep(i,N)cin>>C[i];

    vector<bool> visited(N);

    VV G;
    rep(i,N){
      if(!visited[i]){
        // i start
        VI A = {i};
        visited[i]=1;
        while(true){
          ll nxt = P[A.back()];
          if(visited[nxt]) break;
          A.push_back(nxt);
          visited[nxt]=1;
        }
        G.push_back(A);
      }
    }
    debug(G);

    ll L = G.size();
    debug("groups", L);

    // 1 cycle score
    VI CY(L);
    rep(i,L){
      VI A = G[i];
      for(ll a : A){
        CY[i] += C[a];
      }
    }

    debug(CY);

    ll ma = MAX(C);
    rep(i,L){
      cerr<<endl; //!!!!!kesu
      VI A = G[i];

      // score cycle
      VI AA;
      rep(_,2){
        for(ll a : A){
          ll p = C[a];
          AA.push_back(p);
        }
      }
      debug(AA);
      AccSum Acc(AA);

      if(CY[i]<=0){
        // サイクル不要
        ll k = min(K, SZ(A));

        ll local_ma = -inf;
        // 長さ全探索
        FOR(len, 1, k+1){
          rep(j,SZ(A)){
            ll sc = Acc.sum(j, j+len-1);
            chmax(local_ma, sc);
          }
        }
        debug(i, local_ma);
        chmax(ma, local_ma);
      }
      else{
        // サイクルする
        debug(K);
        ll num = K/SZ(A);
        ll score = num*CY[i]; // 確定スコア
        debug(score, num, CY[i]);

        // 残り
        ll k = K%SZ(A);
        if(k==0){
          chmax(ma, score);
          // continue;
          k += SZ(A);
          num--;
          score = num*CY[i];
        }
        ll local_ma = -inf;
        // 長さ全探索
        FOR(len, 1, k+1){
          rep(j,SZ(A)){
            ll sc = Acc.sum(j, j+len-1);
            chmax(local_ma, sc);
          }
        }
        chmax(ma, local_ma + score);
      }
    }
    p(ma);
    
    
    return 0;
}

Measured memory_bytes: 3900