#include <iostream>
#include <iomanip>
#include <algorithm>
#include <assert.h>
#include <complex>
#include <utility>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <tuple>
#include <cmath>
#include <bitset>
#include <cctype>
#include <set>
#include <map>
#include <unordered_map>
#include <numeric>
#include <functional>
#define _overload3(_1,_2,_3,name,...) name
#define _rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(ll i=ll(a);i<ll(b);++i)
#define rep(...) _overload3(__VA_ARGS__,repi,_rep,)(__VA_ARGS__)
#define rrep(i,a) for(ll i=ll(a-1);i>=0;--i)
#define all(x) (x).begin(),(x).end()
#define PRINT(V) cout << V << "\n"
#define SORT(V) sort((V).begin(),(V).end())
#define RSORT(V) sort((V).rbegin(), (V).rend())
using namespace std;
using ll = long long;
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; }
inline void Yes(bool condition){ if(condition) PRINT("Yes"); else PRINT("No"); }
template<class itr> void cins(itr first,itr last){
    for (auto i = first;i != last;i++){
        cin >> (*i);
    }
}
template<class itr> void array_output(itr start,itr goal){
    string ans = "",k = " ";
    for (auto i = start;i != goal;i++) ans += to_string(*i)+k;
    if (!ans.empty()) ans.pop_back();
    PRINT(ans);
}
ll gcd(ll a, ll b) {
    return a ? gcd(b%a,a) : b;
}

const ll INF = 1e15;
const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll EPS = 1e-10;
int sgn(const double a){
    return (a < -EPS ? -1 : (a > EPS ? +1 : 0));
}
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> tri;
typedef pair<double,double> point;
typedef complex<double> Point;
const ll MAX = 30000;
constexpr ll nx[8] = {1,0,-1,0,1,-1,1,-1};
constexpr ll ny[8] = {0,1,0,-1,1,1,-1,-1};

int main(){
    //cin.tie(0);
    //ios::sync_with_stdio(false);
    ll n,k;
    cin >> n >> k;
    vector<ll> p(n),c(n);
    rep(i,n){
        cin >> p[i];
        p[i]--;
    }
    cins(all(c));
    vector<bool> done(n,0);
    ll ans = -INF;
    rep(m,n){
        if (done[m]) continue;
        done[m] = 1;
        vector<ll> cnt;
        cnt.push_back(0);
        ll now = p[m],s = 1,sum = c[m],res = 0,plus = c[m];
        while (now != m){
            s++;
            done[now] = 1;
            cnt.push_back(c[now]);
            chmax(plus,c[now]);
            sum += c[now];
            now = p[now];
        }
        cnt.push_back(c[m]);
        sum = 0;
        rep(i,s){
            sum += cnt[i+1];
            cnt.push_back(cnt[i+1]);
        }
        rep(i,s){
            cnt.push_back(cnt[i+1]);
        }
        rep(i,s){
            cnt.push_back(cnt[i+1]);
        }
        //array_output(all(cnt));
        rep(i,4*s){
            cnt[i+1] += cnt[i];
        }
        //array_output(all(cnt));
        //cout << s << endl;
        ll loop = k/s;
        if (loop <= 1){
            rep(i,4*s-k+1){
                rep(j,1,k+1){
                    chmax(ans,cnt[i+j]-cnt[i]);
                }
            }
        }
        else{
            if (sum > 0){
                res += sum*(loop-1);
            }
            ll b = k-s*(loop-1);
            //cout << s << " " << b << endl;
            rep(i,4*s-b+1){
                rep(j,1,b+1){
                    chmax(plus,cnt[i+j]-cnt[i]);
                }
            }
            //cout << sum << " " << plus << " " << res << endl;
            chmax(ans,res+plus);
        }
    }
    PRINT(ans);
}


Measured memory_bytes: 3824