#include<iostream>
#include<algorithm>
#include <iostream> 
#include <algorithm> 
#include<string>
#include<queue>
#include<utility>
#include<fstream>
#include<queue>
#include<set>
#include<stack>
#include<bits/stdc++.h>
#define ll long long int
#define ull unsigned long long int
#define I(a) scanf("%d",&a)
#define I2(a,b) scanf("%d%d",&a,&b)
#define I3(a,b,c) scanf("%d%d%d",&a,&b,&c)
#define L(a) scanf("%lld",&a)
#define L2(a,b) scanf("%lld%lld",&a,&b)
#define L3(a,b,c) scanf("%lld%lld%lld",&a,&b,&c)
#define PI(a) printf("%d",a)
#define PL(a) printf("%lld",a)
#define PT(t) printf("Case %d: ",t)
#define PB push_back
#define x first
#define y second
#define xx first.first
#define xy first.second
#define yx second.first
#define yy second.second
#define SC scanf
#define PC printf
#define NL printf("\n")
#define SET(a) memset(a,0,sizeof a)
#define SETR(a) memset(a,-1,sizeof a)
#define SZ(a) ((int)a.size())-1
#define f(i,a,b) for(int i=a;i<=b; i++)
#define fr(i,a,b) for(int i=a;i<=b; i++)
#define frr(i,a,b) for(int i=a;i>=b; i--)
#define frv(i,a)  for(int i=0;i<a.size();i++)
#define pi 2.0*acos(0.0)
#define R(a) freopen(a, "r", stdin);
#define W(a) freopen(a, "w", stdout);
#define CB(x) __builtin_popcount(x)
#define STN(a) stringtonumber<ll>(a)
#define lol printf("BUG\n")
#define Endl "\n"
#define mk make_pair
using namespace std;
template <class T> inline T BM(T p, T e, T M)
{
    ll ret = 1;
    for(; e > 0; e >>= 1)
    {
        if(e & 1) ret = (ret * p) % M;
        p = (p * p) % M;
    }
    return (T)ret;
}
template <class T> inline T gcd(T a, T b)
{
    if(b == 0)return a;
    return gcd(b, a % b);
}
template <class T> inline T mdINV(T a, T M)
{
    return BM(a, M - 2, M);
}
template <class T> inline T PW(T p, T e)
{
    ll ret = 1;
    for(; e > 0; e >>= 1)
    {
        if(e & 1) ret = (ret * p);
        p = (p * p);
    }
    return (T)ret;
}
 
 
template <class T>bool ISLEFT(T a, T b, T c)
{
    if(((a.xx - b.xx) * (b.yy - c.yy) - (b.xx - c.xx) * (a.yy - b.yy)) < 0.0)return 1;  //Uporer dike //A,b,c, x okkher ordera sorted
    else return 0;
}
 
 
typedef pair<int,int >P;
//////////////////////////
/////////////////////////
int main(){
    int n, m;
    I2(n,m);

    int ar[n+2];
    for(int i = 1;i<=n;i++){
        I(ar[i]);
    }

    int br[n+2];
    for(int i=1;i<=n;i++){
        I(br[i]);
    }
    int mp[n+2];

    ll an = -100000000000000;
    for(int i=1;i <=n;i++){
        SET(mp);
        int x = i;
        vector<int> ans;
        ll sum = 0;
        ll cum =an;
        while(mp[x] == 0){
            mp[x] = 1;
            sum += br[x];
            cum =max(cum, sum);
            ans.push_back(x);
            x = ar[x];
        }
        int sz = ans.size();
        ll   koto = m / sz;

         ll m1 = m % sz;
         ll res = 0;
        ans.push_back(i);
        if(koto){
            koto --;
            if(koto){
                res = koto * sum;
                an = max(an, res);
            }
            ll ke = 0;
            for(int j =1 ;j <= sz; j++){
                res += br[ans[j]];
                ke += br[ans[j]];
                an = max(an, ke);
                an = max(an, res);
            }
        }
         ll ke = 0;
        for(int j =1 ;j <= m1; j++){
            res += br[ans[j]];
            ke += br[ans[j]];
            an = max(an, ke);
            an = max(an, res);
        }
    }
    cout<<an<<endl;
    return 0;
}

Measured memory_bytes: 3820