#include <iostream>
#include <string>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <algorithm>
#include <iomanip>
#include <math.h>
#include <string.h>
#include <cstdio>
#include <tuple>
#include <numeric>
#include <functional>
using namespace std; using ll = long long; using ld = long double;  using pll = pair<ll, ll>;
using vl = vector<ll>; using vll = vector<vl>; using vlll = vector<vll>; using vpll = vector<pll>;
using vs = vector<string>; using tll = tuple<ll, ll, ll>; using vtll = vector<tll>;
template<class T>bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }
const ld PI = 3.1415926535897932;
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define co(i) cout << i << endl;
#define co2(i,j) cout << i << " " << j << endl;
#define co3(i) cout << i << " ";
#define po(i) cout << i.first << " " << i.second << endl;
void in() {}
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail>
void debug_out(Head h, Tail... t) {
	cerr << " " << h;
	if (sizeof...(t) > 0) cerr << " :";
	debug_out(t...);
}
template <typename T>
ostream& operator<<(ostream& os, vector<T> vec) {
	for (size_t i = 0; i < vec.size(); i++)os << vec[i] << (i + 1 == vec.size() ? "" : " ");
	return os;
}
ll ctoi(char c) {
	switch (c) {
	case '0': return 0; case '1': return 1; case '2': return 2;
	case '3': return 3; case '4': return 4; case '5': return 5;
	case '6': return 6; case '7': return 7; case '8': return 8;
	case '9': return 9;  default: return 0;
	}
}
bool pairCompare(const pll firstElof, pll secondElof)
{
	return firstElof.second < secondElof.second;
}
//**Snippetリスト**//
//rep, vin, all, iteLoop, bitSearch, bitList, nod, LIS, digitDP, treeDP, Rerooting//
//gcdlcm, isPrime, eratos, primeFactorize, Npow, combination, divisor, modinv, doubling//
//dfs, bfs, dijkstra, WarshallFloyd, BellmanFord, UnionFind, Kruskal, RMQ, LCA, FordFulkerson//
ll i, j, k, l; ll N, M, K, H, W, L, X, Y, Z, R, Q, T;
ll MOD = 1000000007, INF = 1LL << 60, ans = 0, z = 0, o = 1;
vl flag, D; vector<vpll> path;
int main() {
	cin >> N >> K;
	vl P(N), C(N);
	for (i = 0; i < N; i++) {
		cin >> P[i];
		P[i]--;
	}
	for (i = 0; i < N; i++) cin >> C[i];
	ll ans = -INF;
	for (ll start = 0; start < N; start++) {
		vl T;
		ll now = start;
		ll next = 0;
		vl flag(N);
		for (i = 0; i < N; i++) {
			flag[i] = -1;
		}
		vl A, B;
		while (true) {
			if (flag[now] != -1) {
				for (i = 0; i < flag[now]; i++) {
					A.push_back(T[i]);
				}
				for (i = flag[now]+1; i < T.size(); i++) {
					B.push_back(T[i]);
				}
				B.push_back(now);
				break;
			}
			T.push_back(now);
			flag[now] = T.size() - 1;
			next = P[now];
			now = next;
		}
		ll p = A.size();
		ll q = B.size();
		//debug(A, B);
		ll pre = 0;
		ll k = K;
		if (k <= p) {
			for (i = 0; i < k; i++) {
				pre += C[A[i]];
				chmax(ans, pre);
			}
		}
		else {
			for (i = 0; i < p; i++) {
				pre += C[A[i]];
				chmax(ans, pre);
			}
			k -= p;
			if (k <= q) {
				for (i = 0; i < k; i++) {
					pre += C[B[i]];
					chmax(ans, pre);
				}
			}
			else {
				ll cycle = 0;
				for (i = 0; i < q; i++) cycle += C[B[i]];
				if (cycle < 0) {
					for (i = 0; i < q; i++) {
						pre += C[B[i]];
						chmax(ans, pre);
					}
				}
				else {
					pre += cycle * ((k / q)-1);
					chmax(ans, pre);
					k=k%q+q;
					for (i = 0; i < k; i++) {
						pre += C[B[i%q]];
						chmax(ans, pre);
					}
				}
				//debug(pre, cycle);
			}
		}
	}
	co(ans);
}







Measured memory_bytes: 3816