//#include <bits/stdc++.h>
#include "bits/stdc++.h"
using namespace std;
typedef long long ll;


#include "boost/multiprecision/cpp_int.hpp"
#include "boost/multiprecision/cpp_dec_float.hpp"
namespace mp = boost::multiprecision;
typedef mp::cpp_int LL;
typedef mp::number<mp::cpp_dec_float<1024>> DD;// 仮数部が1024ビットの浮動小数点数型(TLEしたら小さくする)

 
typedef long double dd;
#define i_7 (ll)(1E9+7)
//#define i_7 998244353
#define i_5 i_7-2
ll mod(ll a){
    ll c=a%i_7;
    if(c>=0)return c;
    return c+i_7;
}
typedef pair<ll,ll> l_l;
typedef pair<dd,dd> d_d;
ll inf=(ll)1E16;
#define rep(i,l,r) for(ll i=l;i<=r;i++)
#define rrep(i,r,l) for(ll i=r;i>=l;i--)
#define pb push_back
ll max(ll a,ll b){if(a<b)return b;else return a;}
ll min(ll a,ll b){if(a>b)return b;else return a;}
void Max(ll &pos,ll val){pos=max(pos,val);}//Max(dp[n],dp[n-1]);
void Min(ll &pos,ll val){pos=min(pos,val);}
void Add(ll &pos,ll val){pos=mod(pos+val);}
dd EPS=1E-12;
#define fastio ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define fi first
#define se second
#define endl "\n"  //インタラクティブで消す！！！！！！！！！！！！！！！！！！！！！
#define SORT(v) sort(v.begin(),v.end())
#define ERASE(v) v.erase(unique(v.begin(),v.end()),v.end())
#define POSL(v,x) (lower_bound(v.begin(),v.end(),x)-v.begin())
#define POSU(v,x) (upper_bound(v.begin(),v.end(),x)-v.begin())
template<class T,class S>
inline bool chmax(T &a, S b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}
template<class T,class S>
inline bool chmin(T &a, S b) {
    if(a > b) {
        a = b;
        return true;
    }
    return false;
}

void mod_print(ll k){
    ll P=50000;
    rep(y,1,P){
        ll x=mod(y*k);
        
        if(abs(x)<=P||x+P>=i_7){
            if(x+P>=i_7){
                x-=i_7;
            }
            cout<<x<<"/"<<y<<endl;
            //cout<<setprecision(5)<<(dd)x/(dd)y;
            return;
        }
    }
    cout<<"nun"<<endl;
}
#define all(c) c.begin(),c.end()
typedef vector<ll> vl;
//////////////////////////

ll n,k;
void check(ll c[]){
    rep(i,0,n-1){
        if(c[i]>0)return;
    }
    ll ans=-inf;
    rep(i,0,n-1){
        chmax(ans,c[i]);
    }
    cout<<ans<<endl;
    exit(0);
}

ll in(ll x){
    rrep(i,60,0){
        if((x>>i)&1)return i+1;
    }
    return 1;
}
int main(){fastio
    inf=(ll)(1E18)+100;
    cin>>n>>k;
    ll p[n],c[n];
    rep(i,0,n-1){cin>>p[i];p[i]--;}
    rep(i,0,n-1)cin>>c[i];
    check(c);
    if(k==1){
        ll ans=-inf;
        rep(i,0,n-1){
            chmax(ans,c[i]);
        }
        cout<<ans<<endl;
        return 0;
    }
    ll M=in(k);
    ll nx[n][M];
    rep(j,0,M-1){
        rep(i,0,n-1){
            if(j==0){
                nx[i][j]=p[i];
            }else{
                nx[i][j]=nx[nx[i][j-1]][j-1];
            }
        }
    }
    /*
    rep(i,0,n-1){
        rep(j,0,M-1)cout<<nx[i][j]<<" ";cout<<endl;
    }*/
    
    ll po[n][M];
    rep(j,0,M-1){
        rep(i,0,n-1){
            if(j==0){
                po[i][j]=c[p[i]];
            }else{
                po[i][j]=po[i][j-1]+po[nx[i][j-1]][j-1];
            }
        }
    }
    /*
    rep(i,0,n-1){
        rep(j,0,M-1){
            cout<<po[i][j]<<" ";
        }cout<<endl;
    }cout<<endl;*/
    ll dp[M+1][n][2];
    rep(i,0,M)rep(j,0,n-1)rep(l,0,1)dp[i][j][l]=-inf;
    rep(j,0,n-1)dp[M][j][1]=0;
    rrep(i,M-1,0){
        rep(j,0,n-1){
            ll nj=nx[j][i];
            ll ad=po[j][i];
            if((k>>i)&1){
                chmax(dp[i][nj][1],ad+dp[i+1][j][1]);
                chmax(dp[i][j][0],dp[i+1][j][1]);
                chmax(dp[i][nj][0],ad+dp[i+1][j][0]);
                chmax(dp[i][j][0],dp[i+1][j][0]);
            }else{
                chmax(dp[i][j][1],dp[i+1][j][1]);
                chmax(dp[i][nj][0],ad+dp[i+1][j][0]);
                chmax(dp[i][j][0],dp[i+1][j][0]);
            }
        }
    }
    /*
    rep(i,0,M){
        rep(j,0,n-1){
            rep(l,0,1){
                cout<<dp[i][j][l]<<" ";
            }cout<<endl;
        }cout<<endl;
    }cout<<endl;
    */
    ll ans=0;
    rep(i,0,M){
        rep(j,0,n-1){
            rep(l,0,1){
                chmax(ans,dp[i][j][l]);
            }
        }
    }
    cout<<ans<<endl;
    return 0;
}



Measured memory_bytes: 8452