#include <algorithm>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iostream>
#include <numeric>
#include <queue>
#include <string>
#include <utility>
#include <vector>

using namespace std;
#define ALL(a) (a).begin(), (a).end()
#define REP(i, n) for (size_t i = 0; i < (n); i++)
#define nvec(T, v, n) vector<T> v(n); REP(i, n) {cin>>(v)[i];}
#define npairs(T1, T2, v, n) vector<pair<T1, T2>> v(n); REP(i, n){cin>>v[i].first>>v[i].second;}
#define ntuples(T1, T2, T3, v, n) vector<tuple<T1, T2, T3>> v(n); REP(i, n){cin>>get<0>(v[i])>>get<1>(v[i])>>get<2>(v[i]);}
#define vec2d(T, v, m, n) vector<vector<T>> (v)(m, vector<T>(n))
#define nvec2d(T, v, m, n) vec2d(T, v, m, n); REP(j, m){REP(i, n) {cin>>(v[j])[i];}}

#define min_index(v) size_t( min_element(all(v)) - (v).begin() )
#define max_index(v) size_t( max_element(all(v)) - (v).begin() )
#define min_e(v) *min_element(ALL(v))
#define max_e(v) *max_element(ALL(v))

#define count_le(v, a) size_t( upper_bound(ALL(v), a) - (v).begin() )
#define count_lt(v, a) size_t( lower_bound(ALL(v), a) - (v).begin() )
#define count_ge(v, a) size_t( (v).end() - lower_bound(ALL(v), a) )
#define count_gt(v, a) size_t( (v).end() - upper_bound(ALL(v), a) )

#define order(neq_sl) [](const auto s, const auto l){return neq_sl;}
#define make_lr(v,type,l,r) vector<type> l(n+1),r(n+1);FOR(i,n){l[i+1]=l[i]+v[i];r[i+1]=r[i]+v[n-1-i];}

#define acm accumulate
#define SUM(v) accumulate(ALL(v), 0l)
#define SORT(v) sort(ALL(v))

#define GCD(v) gcd(ALL(v), 0l)

/*template <typename T>
T gcd(T a, T b) {
    if (a > b) swap(a, b);
    if (a == 0) return b;
    return gcd(b%a, a);
}
template <typename InputItr, typename T>
T gcd(InputItr first, InputItr last, T init) {
    for (; first != last; ++first) init = gcd(init, *first);
    return init;
}*/

template <typename T>
using vec = vector<T>;

template <typename T>
using vvec = vector<vector<T>>;

class cycle {
public:
  cycle(){
    score=0;
    len=0;
    elems={};
  }
  long score;
  int len;
  vector<int> elems; 
};


int main(){
  int n,k;
  cin>>n>>k;
  nvec(int,p,n);
  nvec(int,c,n);
  for (int i = 0; i < n; i++) {
    p[i]--;
  }
  vvec<long> score(n, vector<long>(1,0));
  
  vec<cycle> cycles;
  vec<int> isCycle(n, -1);
  int cyclenum = 0;
  
  for (int i = 0; i < n; i++) {
    if (isCycle[i] == -1) {
      cycle cc; int e = i;
      do {
        cc.elems.push_back(e);
        cc.len++;
        isCycle[e] = cyclenum;
        e = p[e];
        score[i].push_back(cc.score += c[e]);
      } while (e != i);
      cycles.push_back(cc);
      cyclenum++;
    } else {
      for (int e = p[i];; e = p[e]) {
        score[i].push_back(c[e] + score[i].back());
        if (e == i) break;
      }
    }
  }

  long ans = -100000000000;
  
  for (cycle cc: cycles) {
    long s = cc.score * (k / cc.len); int m = k % cc.len;
    for (int e: cc.elems) {
      if (s > 0) {
        for (int i = 0; i <= m; i++) {
          ans = max(ans, s + score[e][i]);
        }
        for (int i = 0; i < cc.len-m; i++) {
          ans = max(ans, s - score[e][i]);
        }
      } else {
         
        for (int i = 1; i <= min(k, cc.len); i++) {
          ans = max(ans, score[e][i]);
        }
       
      }
    }
  }
  cout<<ans;
}

Measured memory_bytes: 218928