#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> P;
typedef pair<int,int> Pi;
#define rep(i,n) for(ll i=0;i<n;i++)
#define FOR(i,a,b) for(ll i=a;i<b;i++)
#define fi first
#define se second
#define endl "\n"

template<typename T> inline bool chmax(T &a, T b){if(a<b){a=b;return true;}return false;}
template<typename T> inline bool chmin(T &a, T b){if(a>b){a=b;return true;}return false;}
template<typename T> ostream& operator<<(ostream& s,const complex<T>& d) {return s<<"("<<d.real()<<", "<<d.imag()<< ")";}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const pair<T1,T2>& d) {return s<<"("<<d.first<<", "<<d.second<<")";}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& d){int len=d.size();rep(i,len){s<<d[i];if(i<len-1) s<<" ";}return s;}
template<typename T> ostream& operator<<(ostream& s,const vector<vector<T>>& d){int len=d.size();rep(i,len){s<<d[i]<<endl;}return s;}
template<typename T> ostream& operator<<(ostream& s,const set<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T> ostream& operator<<(ostream& s,const multiset<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const map<T1,T2>& m){s<<"{"<<endl;for(auto itr=m.begin();itr!=m.end();++itr){s<<" "<<(*itr).first<<" : "<<(*itr).second<<endl;}s<<"}"<<endl;return s;}

const ll mod=1'000'000'007;
const ll inf=1'000'000'000'000'000'00;
const int INF=1'000'000'000;
const double EPS=1e-10;
const double PI=acos(-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]--;
    }
    bool flag=true;
    rep(i,n){
        cin>>c[i];
        if(c[i]>0) flag=false;
    }
    if(flag){//全部負だったら
        cout<<*max_element(begin(c),end(c))<<endl;
        return 0;
    }
    //答えは絶対正になる
    ll ans=0;
    rep(st,n){
        queue<ll> que;
        que.push(st);
        vector<ll> dp(n,-inf);
        dp[st]=0;
        ll cnt=0;
        while(!que.empty()){
            auto v=que.front();
            que.pop(); 
            if(cnt==k) break;
            ll to=p[v];
            if(dp[to]==-inf){
                que.push(to);
                cnt++;
                dp[to]=dp[v]+c[to];
            }else{
                ll roop=dp[v]+c[to]-dp[to];
                if(roop<0) break;
                dp[to]+=roop;
                cnt++;
                ll num=0;
                for(ll i=to;;i=p[i]){
                    num++;
                    if(i==v) break;
                }
                ll ret=k-cnt;
                if(ret>=num){
					dp[to]+=roop*(ret/num-1);
					ret%=num;
					ret+=num;
				}
                ll now=to;
                while(ret--){
                    dp[p[now]]=dp[now]+c[p[now]];
                    now=p[now];
					chmax(ans,dp[now]);
                }
                break;
            }
        }
        rep(i,n){
            chmax(ans,dp[i]);
        }
    }
    cout<<ans<<endl;
}

Measured memory_bytes: 3724