#include<iostream>
#include<cassert>
#include<cctype>
#include<cerrno>
#include<cfloat>
#include<vector>
#include<algorithm>
#include<string>
#include<map>
#include<math.h>
#include<queue>
#include<deque>
#include<stack>
#include<cstdio>
#include<utility>
#include<set>
#include<list>
#include<cmath>
#include<stdio.h>
#include<string.h>
#include<iomanip>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<bitset>
#include<functional>
#include<iterator>
#include<complex>
#include<fstream>
#include<random>
#include<ctype.h>
#include<stdio.h>
#include<unordered_map>
using namespace std;
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define REP(i, n) FOR(i, 0, n - 1)
#define NREP(i, n) FOR(i, 1, n)
using ll = long long;
using pii = pair<int, int>;
using PII = pair<ll, ll>;
using piii = pair<pii, pii>;
using Pi = pair<int, pii>;
using Graph = vector<vector<int>>;
const int dx[4] = { 0, -1, 1, 0 };
const int dy[4] = { -1, 0, 0, 1 };
bool check(int x, int y) {
	if (0 <= x && x<55 && 0 <= y && y<55)return true;
	else return false;
}
const ll INF = 1e9 + 7;
int gcd(int x, int y) {
	if (x < y)swap(x, y);
	if (y == 0)return x;
	return gcd(y, x%y);
}
void mul(ll a, ll b) {
	a = a * b % INF;
}
using Graph = vector<vector<int>>;

//iの逆元mod inf
long long modinv(long long a, long long m) {
	long long b = m, u = 1, v = 0;
	while (b) {
		long long t = a / b;
		a -= t * b; swap(a, b);
		u -= t * v; swap(u, v);
	}
	u %= m;
	if (u < 0) u += m;
	return u;
}
const double PI = 3.14159265358979323846;
const int MAX = 510000;
ll fac[MAX], finv[MAX], inv[MAX];
//テーブルをつくる前処理
void COMinit() {
	fac[0] = fac[1] = 1;
	finv[0] = finv[1] = 1;
	inv[1] = 1;//mod pにおける1,2,,,nの逆元
	for (int i = 2; i < MAX; ++i) {
		fac[i] = fac[i - 1] * i%INF;
		inv[i] = INF - inv[INF%i] * (INF / i) % INF;
		finv[i] = finv[i - 1] * inv[i] % INF;
	}
}

ll COM(int n, int k) {
	if (n < k)return 0;
	if (n < 0 || k < 0)return 0;
	return fac[n] * (finv[k] * finv[n - k] % INF) % INF;
}
double Euclidean_distance(double x1, double y1, double x2, double y2) {
	return sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}

//素因数分解
map<int, int>prime_factor(int n) {
	map<int, int>res;
	for (int i = 2; i*i <= n; ++i) {
		while (n%i == 0) {
			++res[i];
			n /= i;
		}
	}
	if (n != 1)res[n] = 1;
	return res;
}


ll powmod(ll a, ll k, ll mod) {
	ll ap = a, ans = 1;
	while (k) {
		if (k & 1) {
			ans *= ap;
			ans %= mod;
		}
		ap = ap * ap;
		ap %= mod;
		k >>= 1;
	}
	return ans;
}
ll invi(ll a, ll mod) {
	return powmod(a, mod - 2, mod);
}
#define PI 3.14159265358979323846  // 円周率
//逆元Aを足したときのmodで割った余りは
//+=invi(A)
//Yで割ることはY^(10^9+7)-2を掛けることは同値
///////////////////////////////////////

int n, k;
//順列だから必ずいくつかのサイクルになるどこから出発してもいつかそこに戻る
//おおまかに次のパターンしか存在しない
//サイクルを一周して得られるスコアの総和が正の時:最初に何個かとった後ひたすら目いっぱい回す
//サイクルを一周して得られるスコアの総和が０以下の時:循環するm個のうちの連続する区間の総和の最大値
int main() {
	cin >> n >> k;
	vector<int>p(n), c(n);
	REP(i, n)cin >> p[i], --p[i];
	REP(i, n)cin >> c[i];
	ll ans = -INF;
	//始点を固定して回す
	REP(i, n) {
		int v = i;
		ll cycle_sum = 0;
		int cycle_cnt = 0;
		ll cycle_max = -INF;
		vector<ll>cycle;
		cycle.push_back(0);
		while (true) {
			cycle_cnt++;
			cycle_sum += c[v];
			cycle.push_back(cycle[cycle_cnt - 1] + c[v]);
			cycle_max = max(cycle_max, cycle_sum);
			v = p[v];
			if (v == i)break;
		}
		ll path = 0;
		int cnt = 0;
		if (k <= cycle_cnt) {
			for (int j = 1; j <= k;++j) {
				ans = max(ans, cycle[j]);
			}
		}
		else {
			if (cycle_sum <= 0) {
				for (int j = 1; j <= cycle_cnt; ++j) {
					ans = max(ans, cycle[j]);
				}
			}
			else {
				for (int j = 1; j <= cycle_cnt; ++j) {
					int num = (k - j) / cycle_cnt;
					ll score = cycle[j] + cycle_sum*num;
					ans = max(ans, score);
				}
			}
		}
	}
	cout << ans << endl;
	return 0;
}


Measured memory_bytes: 3780