#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define pli pair<ll, int>
#define pil pair<int, ll>
#define pll pair<ll, ll>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define endl '\n'
const int inf = 1000000007;
const ll INF = 1e18;
// int mod = 998244353;
int mod = 1000000007;
const double eps = 1e-8;
#define abs(x) (x >= 0 ? x : -(x))
#define lb(v, x) (int)(lower_bound(all(v), x) - v.begin())
#define ub(v, x) (int)(upper_bound(all(v), x) - v.begin())
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return 1; } return 0; }
ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); }
ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }
template<typename T, typename U> T pow_(T a, U b) { return b ? pow_(a * a, b / 2) * (b % 2 ? a : 1) : 1; }
ll modpow(ll a, ll b, ll _mod) { return b ? modpow(a * a % _mod, b / 2, _mod) * (b % 2 ? a : 1) % _mod : 1; }
template<class T, class U> ostream& operator << (ostream& os, const pair<T, U>& p) { os << p.F << " " << p.S; return os; }
template<class T> ostream& operator << (ostream& os, const vector<T>& vec) { rep(i, sz(vec)) { if (i) os << " "; os << vec[i]; } return os; }
template<class T> ostream& operator << (ostream& os, const set<T>& s) { for (auto si : s) os << si << " "; return os; }
template<typename T> inline istream& operator >> (istream& is, vector<T>& v) { rep(j, sz(v)) is >> v[j]; return is; }
template<class T, class T2> inline void add(T &a, T2 b) { a += b % mod; if (a >= mod) a -= mod; }
template<class T> void operator += (vector<T>& v, vector<T> v2) { rep(i, sz(v2)) v.eb(v2[i]); }

void solve();

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(12); // debuged
    int T;
    T = 1;
    while (T--) solve();
}

// https://atcoder.jp/contests/abc175/submissions/15967390
// vに入れる順番がおかしい
void solve() {
    int n, k;
    cin >> n >> k;
    vector<int> p(n), c(n);
    cin >> p >> c;
    rep(i, n) --p[i];
    
    vector<int> visited(n, -1);
    vector<vector<int> > v(n);
    rep(i, n) { // O(N)
        if (visited[i] != -1) continue;
        int now = i;
        while (1) {
            visited[now] = i;
            v[i].eb(c[now]);
            
            now = p[now];
            if (visited[now] != -1) break;
        }
    }
    // cerr << "vis " << visited << endl;
    
    ll ans = *max_element(all(c));
    if (ans <= 0) {
        cout << ans << endl;
        return;
    }
    
    rep(i, n) {
        if (sz(v[i]) == 0) continue;
        ll sum = accumulate(all(v[i]), 0LL);
        // cerr << v[i] << "  " << sum << endl;
        
        // 長さ2倍にして, 取る連続区間を探索
        int sz_ = sz(v[i]);
        rep(j, sz_) v[i].eb(v[i][j]);
        rep(j, sz(v[i])) {
            ll sum_ = 0;
            // cerr << j << " " << k << " " << sz(v[i]) / 2 << endl;
            rep3(l, j, j + min(k, sz_)) {
                if (l == sz(v[i])) break;
                sum_ += v[i][l];
                if (sum > 0) chmax(ans, sum_ + max(0, k - (l - j + 1)) / sz_ * sum);
                chmax(ans, sum_);
            }
        }
    }
    cout << ans << endl;
}


Measured memory_bytes: 3920