/*
このコード、と～おれ!
Be accepted!
∧＿∧　
（｡･ω･｡)つ━☆・*。
⊂　　 ノ 　　　・゜+.
　しーＪ　　　°。+ *´¨)
 　　　　　　　　　.· ´¸.·*´¨) ¸.·*¨)
		  　　　　　　　　　　(¸.·´ (¸.·'* ☆
*/

#include <cstdio>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstring>
#include <vector>
#include <numeric>
#include <iostream>
#include <random>
#include <map>
#include <unordered_map>
#include <queue>
#include <regex>
#include <functional>
#include <complex>
#include <list>
#include <cassert>
#include <iomanip>
#include <set>
#include <stack>
#include <bitset>

////多倍長整数, cpp_intで宣言
//#include <boost/multiprecision/cpp_int.hpp>
//using namespace boost::multiprecision;

//#pragma gcc target ("avx2")
//#pragma gcc optimization ("o3")
//#pragma gcc optimization ("unroll-loops")
#define repeat(i, n, m) for(int i = n; i < (m); ++i)
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define printynl(a) printf(a ? "yes\n" : "no\n")
#define printyn(a) printf(a ? "Yes\n" : "No\n")
#define printYN(a) printf(a ? "YES\n" : "NO\n")
#define printim(a) printf(a ? "possible\n" : "imposible\n")
#define printdb(a) printf("%.50lf\n", a) //少数出力
#define printLdb(a) printf("%.50Lf\n", a) //少数出力
#define printdbd(a) printf("%.16lf\n", a) //少数出力(桁少なめ)
#define prints(s) printf("%s\n", s.c_str()) //string出力
#define all(x) (x).begin(), (x).end()
#define deg_to_rad(deg) (((deg)/360.0L)*2.0L*PI)
#define rad_to_deg(rad) (((rad)/2.0L/PI)*360.0L)
#define Please return
#define AC 0
#define manhattan_dist(a, b, c, d) (abs(a - c) + abs(b - d)) /*(a, b) から (c, d) のマンハッタン距離 */
#define inf numeric_limits<double>::infinity();
#define linf numeric_limits<long double>::infinity()

using ll = long long;
using ull = unsigned long long;

constexpr int INF = 1073741823;
constexpr int MINF = -1073741823;
constexpr ll LINF = ll(4661686018427387903);
constexpr ll MOD = 1e9 + 7;
constexpr ll mod = 998244353;
constexpr long double eps = 1e-6;
const long double PI = acosl(-1.0L);

using namespace std;

void scans(string& str) {
	char c;
	str = "";
	scanf("%c", &c);
	if (c == '\n')scanf("%c", &c);
	while (c != '\n' && c != -1 && c != ' ') {
		str += c;
		scanf("%c", &c);
	}
}

void scanc(char& str) {
	char c;
	scanf("%c", &c);
	if (c == -1)return;
	while (c == '\n') {
		scanf("%c", &c);
	}
	str = c;
}


double acot(double x) {
	return PI / 2 - atan(x);
}

ll LSB(ll n) { return (n & (-n)); }

template<typename T>
T chmin(T& a, const T& b) {
	if (a > b)a = b;
	return a;
}

template<typename T>
T chmax(T& a, const T& b) {
	if (a < b)a = b;
	return a;
}

/*-----------------------------------------ここからコード-----------------------------------------*/



int main() {

	int n;
	ll k;
	scanf("%d%lld", &n, &k);
	vector<ll> p(n), c(n);
	vector<pair<ll, ll>> score(n);
	rep(i, n) {
		scanf("%lld", &p[i]);
		--p[i];
	}
	rep(i, n)scanf("%lld", &c[i]);
	rep(i, n) {
		ll cur = p[i], cnt = 1;
		ll sum = 0;
		while (cur != i) {
			sum += c[cur];
			cur = p[cur];
			++cnt;
		}
		sum += c[cur];
		score[i] = { sum, cnt };
	}
	ll ans = *max_element(all(c)), tmp = 0;
	ll ktmp = k, now = 0, cur = 0;
	for (const auto& [sum, cnt] : score) {
		cur = now;
		++now;
		k = ktmp;
		tmp = 0;
		vector<ll> add, del;
		if (sum >= 0) {
			tmp += sum * (k / cnt);
			k -= (k / cnt) * cnt;
			chmax(ans, tmp);
			add.push_back(0);
		}
		chmin(k, cnt);
		for (int i = 0; k--; ++i) {
			cur = p[cur];
			if (i)add.push_back(add.back() + c[cur]);
			else add.push_back(c[cur]);
		}
		ll ad = *max_element(all(add));
		if (sum >= 0) {
			add = {0};
			cur = p[now - 1];
			while (cur != now - 1) {
				add.push_back(add.back() + c[cur]);
				cur = p[cur];
			}
			add.push_back(add.back() + c[cur]);
			chmax(ad, *max_element(all(add)) - sum);
		}
		tmp += ad;
		chmax(ans, tmp);
	}
	printf("%lld\n", ans);

	Please AC;
}


Measured memory_bytes: 4008