#include <algorithm>
#include <iostream>
#include <vector>
#include <math.h>
#include <set>
#include <map>
#include <string>
#include <stack>
#include <queue>
#include <iomanip>
#include <numeric>
#include <tuple>
#include <bitset>
#include <complex>
#include <unistd.h>
#include <cassert>
#include <cctype>
#include <random>
#include <time.h>
#include <functional>
#define _USE_MATH_DEFINES
#define _GLIBCXX_DEBUG
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> plglg;
typedef pair<double, ll> pdlg;
typedef tuple<int, int, int> tiii;
typedef tuple<ll, ll, ll> tlglglg;
typedef tuple<ll, ll, ll, ll> tlglglglg;
typedef tuple<double, double, double> tddd;
typedef complex<double> xy_t;
typedef vector<ll> vll;
typedef vector< vector<ll> > matrix;
typedef unsigned int uint;
typedef unsigned long long ull;
template <class T> using V = vector<T>;
template <class T> using VV = V<V<T>>;
template <class T> using VVV = V<VV<T>>;
#define REP(i, x, y) for(ll i = (ll)x; i < (ll)y; i++)
#define DREP(i, x, y, d) for(ll i = (ll)x; i < (ll)y; i += (ll)d)
#define PER(i, x, y) for(ll i = (ll)x; i > (ll)y; i--)
#define DPER(i, x, y, d) for(ll i = (ll)x; i > (ll)y; i -= (ll)d)
int dx[4] = {1, 0, -1, 0};
int dy[4] = {0, 1, 0, -1};
double pi = 3.141592653589793;
ll mod = 1000000007;
int intmax = 2147483647;
int intmin = -2147483648;
ll llmax = 9223372036854775807;
ll llmin = -9223372036854775807;
int iinf = intmax / 8;
ll inf = llmax / 8;
double eps = 1e-12;
void yesno(bool ok, string yes = "Yes", string no = "No") {
    if (ok) {
        cout << yes << endl;
    } else {
        cout << no << endl;
    }
}

ll bo[5010];
ll bofirst[5010];
ll firstnum[5010];
ll used[5010];

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    ll N, K;
    cin >> N >> K;
    ll P[N], C[N];
    REP(i, 0, N) {
        cin >> P[i];
    }
    REP(i, 0, N) {
        cin >> C[i];
    }
    ll ans = -inf;
    REP(i, 0, N) {
        fill(bo, bo + N, -inf);
        fill(bofirst, bofirst + N, -inf);
        fill(firstnum, firstnum + N, 0);
        fill(used, used + N, 0);
        ll now = i;
        ll tmp = 0;
        bool loop = false;
        REP(j, 0, K) {
            now = P[now] - 1;
            tmp += C[now];
            if (used[now] == 2) {
                loop = true;
                break;
            }
            used[now]++;
            if (used[now] == 1) {
                bofirst[now] = tmp;
                firstnum[now] = j + 1;
            }
            bo[now] = max(bo[now], tmp);
        }
        ll two = 0;
        REP(j, 0, N) {
            if (used[j] == 2) {
                two++;
            }
        }
        if (loop) {
            REP(j, 0, N) {
                if (used[j] == 1) {
                    ans = max(ans, bo[j]);
                } else if (used[j] == 2) {
                    ll p = bofirst[j];
                    ll num = (K - firstnum[j]) / two;
                    p += num * (bo[j] - bofirst[j]);
                    ans = max(ans, p);
                }
            }
        } else {
            REP(j, 0, N) {
                if (used[j] >= 1) {
                    ans = max(ans, bo[j]);
                }
            }
        }
        // REP(j, 0, N) {
        //     cout << bo[j] << " " << bofirst[j] << " " << used[j] << " " << firstnum[j] << endl;
        // }
        // cout << ans << " aaa" << endl;
    }
    cout << ans << endl;
}


Measured memory_bytes: 3884