#include<bits/stdc++.h>
//ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
//clock_t start=clock();clock_t end=clock();cout<<(double)(end-start)/CLOCKS_PER_SEC<<endl;
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;
typedef pair<int,int> pii;
typedef pair<pii,int> ppii;
typedef pair<int,pii> pipi;
typedef pair<ll,ll> pll;
typedef pair<pll,ll> ppll;
typedef pair<ll,pll> plpl;
typedef pair<pii,pii> pippi;
typedef tuple<ll,ll,ll> tl;
typedef pair<double,double> pdd;
typedef vector<vector<ll>> mat;
ll mod=1000000007;
ll mod2=998244353;
ll mod3=1000003;
ll mod4=998244853;
ll mod5=1000000009;
ll inf=1LL<<61;
int iinf=1<<30;
double pi=3.14159265358979323846;
double pi2=pi/2.0;
double eps=1e-8;
#define rep(i,m,n) for(int i=m;i<n;i++)
#define rrep(i,n,m) for(ll i=n;i>=m;i--)
#define srep(itr,st) for(auto itr=st.begin();itr!=st.end();itr++)
#define mrep(itr,mp) for(auto& itr:mp)
#define Max(a,b) a=max(a,b)
#define Min(a,b) a=min(a,b)
//#define endl "\n"
int dh[4]={1,0,-1,0};
int dw[4]={0,1,0,-1};
int ddh[8]={-1,-1,-1,0,0,1,1,1};
int ddw[8]={-1,0,1,-1,1,-1,0,1};
struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};
#define umh unordered_map<int,int,custom_hash>
ll gcd(ll a,ll b){
    if(a<0)a=-a;
    if(b<0)b=-b;
    if(a<b)swap(a,b);
    if(b==0)return a;
    if(a%b==0)return b;
    return gcd(b,a%b);
}
ll lcm(ll a,ll b){
    ll c=gcd(a,b);
    return a*b/c;
}
ll Pow(ll n,ll k){
    if(k<0)return 0;
    ll ret=1;
    ll now=n;
    while(k>0){
        if(k&1)ret*=now;
        now*=now;
        k/=2;
    }
    return ret;
}
ll beki(ll n,ll k,ll md){
  ll ret=1;
  ll now=n;
    now%=md;
  while(k>0){
    if(k%2==1){
      ret*=now;
      ret%=md;
    }
    now*=now;
    now%=md;
    k/=2;
  }
  return ret;
}
ll gyaku(ll n,ll md){
  return beki(n,md-2,md);
}
ll popcount(ll n){
    ll ret=0;
    ll u=n;
    while(u>0){
        ret+=u%2;
        u/=2;
        
    }
    return ret;
}

int main(){
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    ll n,k;cin>>n>>k;
    ll p[n];
    rep(i,0,n){
        cin>>p[i];
        p[i]--;
    }
    ll c[n];
    rep(i,0,n)cin>>c[i];
    ll cnt[n];
    ll ans=-inf;
    ll kai[n];
    rep(i,0,n){
        fill(cnt,cnt+n,-inf);
        fill(kai,kai+n,-1);
        ll now=i;
        ll num=0;
        ll sum=0;
        for(;;){
            now=p[now];
            if(kai[now]!=-1){
                ll syu=num+1-kai[now];
                ll syus=sum-(cnt[now]-c[now]);
                ll haji=kai[now]-1;
                if(syus<=0)break;
                ll noko=k-haji;
                ll syou=noko/syu;
                ll ama=noko%syu;
                sum=syou*syus+cnt[now]-c[now];
                ll ima=now;
                Max(ans,sum);
                rep(j,0,ama){
                    sum+=c[now];
                    Max(ans,sum);
                    now=p[now];
                }
                now=ima;
                sum=(syou-1)*syus+cnt[now]-c[now];
                //cout<<sum<<endl;
                Max(ans,sum);
                now=ima;
                rep(j,0,syu){
                    sum+=c[now];
                    Max(ans,sum);
                    now=p[now];
                }
                break;
            }
            num++;
            sum+=c[now];
            Max(ans,sum);
            cnt[now]=sum;
            kai[now]=num;
            if(num==k)break;
        }
    }
    cout<<ans<<endl;
}



Measured memory_bytes: 3792