#include <bits/stdc++.h>
using namespace std;
#define REP(i,x,n) for(int i=x;i<(int)n;i++)
#define rep(i,n) REP(i,0,n)
#define sp(p) cout<<setprecision(16)<<fixed<<p<<endl;
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define SORT(a) sort(all(a))
#define RSORT(a) sort(rall(a))
#define UNIQ(a) unique(all(a))
#define UNIQNUM(a) UNIQ(a)-a.begin()
#define UNIQIT(a) a.erase(UNIQ(a), a.end());
#define VOUT(v,i) rep(i,v.size())cout<<v[i]<<(i==v.size()-1?"\n":" ");
#define vout(v) VOUT(v,z);
#define vdbg(v,i) cout<<#v<<": ";for(int i=0;i<(int)v.size();i++){cout<<v[i]<<" ";}cout<<"\n";
#define vmin(v) *min_element(all(v))
#define vmax(v) *max_element(all(v))
#define vsum(v) accumulate(all(v), 0LL)
#define MOUT(m,r,c) rep(i,r){rep(j,c){cout<<m[i][j]<<" ";}cout<<endl;}
#define mout(m) MOUT(m,m.size(),m[0].size())
#define debg(a) cout<<#a<<": "<<a<<endl;
#define show(a) for(cont &y:a){for(cont &x:y){cout<<x<<" ";}cout<<endl;}
#define digit(a) to_string(a).length();
template<class T>inline int out(const T &t){ print(t); putchar('\n'); return 0; }
// 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 lcm(T a,T b){return a/gcd(a,b)*b;}
bool is_palindrome(string s){return s == string(s.rbegin(),s.rend());}
#define popcount __builtin_popcount
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> P;
typedef vector<ll> V;
typedef vector<vector<ll>> VV;
// const long long MOD=1000000007;
const long long INF = 1e18;
#define EPS (1e-7)
#define PI (acos(-1))
template<class T>
inline bool chmax(T &a, T b) {
    if(a < b) { a = b; return true; }
    return false;
}
template<class T>
inline bool chmin(T &a, T b) {
    if(a > b) { a = b; return true; }
    return false;
}



int main(){
    long long N;
    scanf("%lld",&N);
    long long K;
    scanf("%lld",&K);
    std::vector<long long> P(N+1);
    for(int i = 1 ; i <= N ; i++){
        scanf("%lld",&P[i]);
    }
    std::vector<long long> C(N+1);
    for(int i = 1 ; i <= N ; i++){
        scanf("%lld",&C[i]);
    }

    // ll ret=-INF;
    // for (long long i = 1; i <= N; i++) {
    //     ll start=i;
    //     ll now=start;
    //     ll score=0;
    //     ll roundscore=0;
    //     ll maxscore=-INF;
    //     ll loopcnt=0;
    //     do {
    //         now=P[now];
    //         roundscore+=C[now];
    //         chmax(maxscore, roundscore);
    //         loopcnt++;
    //     } while (start!=now);
    //     if(loopcnt<K){
    //         ll r = K/loopcnt;
    //         if(roundscore>0) score += (r*roundscore);
    //         chmax(maxscore, score);
    //         for (long long j = 0; j < K-loopcnt*r; j++) {
    //             now=P[now];
    //             score+=C[now];
    //             chmax(maxscore, score);
    //         }
    //     }
    //     chmax(ret, maxscore);
    // }
    // cout << ret << endl;

    ll ret=-INF;
    for (long long i = 1; i <= N; i++) {
        ll now=i;
        vector<ll> v;
        ll score=0;
        ll maxscore=-INF;
        do {
            now=P[now];
            score+=C[now];
            v.push_back(score);
        } while (now!=i);
        for (long long j = 0; j < v.size(); j++) {
            if(j+1>K) break;
            ll cnt = (K-j-1)/v.size();
            if(score<=0){
                chmax(maxscore, v[j]);
            }else{
                chmax(maxscore, v[j] + cnt * score);
            }
        }
        chmax(ret, maxscore);
    }
    cout << ret << endl;

    return 0;
}


Measured memory_bytes: 3848