//@formatter:off
#include<bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < int(n); ++i)
#define rrep(i,n) for (int i = int(n)-1; i >= 0; i--)
#define rep2(i,s,n) for (int i = int(s); i < int(n); ++i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#define vi vector<int>
#define vvi vector<vector<int>>
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vd vector<double>
#define vvd vector<vector<double>>
#define vs vector<string>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>>
#define vp vector<P>
#define vvp vector<vector<P>>
using namespace std;
using ll = long long;
using P = pair<int,int>;
using LP = pair<ll,ll>;
template<class S,class T> istream& operator>>(istream &is,pair<S,T> &p) { return is >> p.first >> p.second; }
template<class S,class T> ostream& operator<<(ostream &os,const pair<S,T> &p) { return os<<'{'<<p.first<<","<<p.second<<'}'; }
template<class T> istream& operator>>(istream &is,vector<T> &v) { for(T &t:v){is>>t;} return is; }
template<class T> ostream& operator<<(ostream &os,const vector<T> &v) { os<<'[';rep(i,v.size())os<<v[i]<<(i==int(v.size()-1)?']':','); return os; }
void Yes(bool b) { cout << (b ? "Yes" : "No") << '\n'; }
void YES(bool b) { cout << (b ? "YES" : "NO") << '\n'; }
template<class T> bool chmin(T& a,T b) {if(a > b){a = b; return true;} return false;}
template<class T> bool chmax(T& a,T b) {if(a < b){a = b; return true;} return false;}
const int inf = 1001001001;
const ll linf = 1001001001001001001;
//@formatter:on

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, k;
    cin >> n >> k;
    vi p(n), c(n);
    cin >> p >> c;
    rep(i, n) p[i]--;
    if (k <= n) {
        ll ans = -linf;
        rep(i, n) {
            ll l = 0;
            int now = i;
            rep(_, k) {
                now = p[now];
                l += c[now];
                chmax(ans, l);
            }
        }
        cout << ans << endl;
        return 0;
    }
    ll ans = -linf;
    vb seen(n);
    rep(i, n) {
        if (seen[i]) continue;
        seen[i] = true;
        vi v;
        v.pb(i);
        int now = i;
        ll sc = c[now];
        while (true) {
            now = p[now];
            if (now == i) break;
            v.pb(now);
            sc += c[now];
            seen[now] = true;
        }
        if (sc <= 0) {
            for (int j : v) {
                ll l = 0;
                now = j;
                rep(_, v.size()) {
                    now = p[now];
                    l += c[now];
                    chmax(ans, l);
                }
            }
        } else {
            ll m = max(0LL, k / (ll) v.size() - 1);
            ll l = sc * m;
            ll rem = k - (ll) v.size() * m;
            if (m > 0) chmax(ans, l);
            for (int j : v) {
                ll nl = 0;
                now = j;
                rep(_, rem) {
                    now = p[now];
                    nl += c[now];
                    chmax(ans, l + nl);
                }
            }
        }
    }
    cout << ans << endl;
}

Measured memory_bytes: 3748