#include "bits/stdc++.h"
using namespace std;
#define int long long
#define REP(i, n) for (int i = 0; i < (int)n; ++i)
#define RREP(i, n) for (int i = (int)n - 1; i >= 0; --i)
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define RFOR(i, s, n) for (int i = (int)n - 1; i >= s; --i)
#define ALL(a) a.begin(), a.end()
#define IN(a, x, b) (a <= x && x < b)
template<class T>istream&operator >>(istream&is,vector<T>&vec){for(T&x:vec)is>>x;return is;}
template<class T>inline void out(T t){cout << t << "\n";}
template<class T,class... Ts>inline void out(T t,Ts... ts){cout << t << " ";out(ts...);}
template<class T>inline bool CHMIN(T&a,T b){if(a > b){a = b;return true;}return false;}
template<class T>inline bool CHMAX(T&a,T b){if(a < b){a = b;return true;}return false;}
constexpr int INF = 1e18;

template<int MOD> struct Fp {
	long long val;
	constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
		if (val < 0) val += MOD;
	}
	constexpr int getmod() { return MOD; }
	constexpr Fp operator - () const noexcept {
		return val ? MOD - val : 0;
	}
	constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
	constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
	constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
	constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
	constexpr Fp& operator += (const Fp& r) noexcept {
		val += r.val;
		if (val >= MOD) val -= MOD;
		return *this;
	}
	constexpr Fp& operator -= (const Fp& r) noexcept {
		val -= r.val;
		if (val < 0) val += MOD;
		return *this;
	}
	constexpr Fp& operator *= (const Fp& r) noexcept {
		val = val * r.val % MOD;
		return *this;
	}
	constexpr Fp& operator /= (const Fp& r) noexcept {
		long long a = r.val, b = MOD, u = 1, v = 0;
		while (b) {
			long long t = a / b;
			a -= t * b; swap(a, b);
			u -= t * v; swap(u, v);
		}
		val = val * u % MOD;
		if (val < 0) val += MOD;
		return *this;
	}
	constexpr bool operator == (const Fp& r) const noexcept {
		return this->val == r.val;
	}
	constexpr bool operator != (const Fp& r) const noexcept {
		return this->val != r.val;
	}
	friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept {
		return os << x.val;
	}
	friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
		if (n == 0) return 1;
		auto t = modpow(a, n / 2);
		t = t * t;
		if (n & 1) t = t * a;
		return t;
	}
};
 

template<class T> struct BiCoef {
	vector<T> fact_, inv_, finv_;
	constexpr BiCoef() {}
	constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
		init(n);
	}
	constexpr void init(int n) noexcept {
		fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
		int MOD = fact_[0].getmod();
		for(int i = 2; i < n; i++){
			fact_[i] = fact_[i-1] * i;
			inv_[i] = -inv_[MOD%i] * (MOD/i);
			finv_[i] = finv_[i-1] * inv_[i];
		}
	}
	constexpr T com(int n, int k) const noexcept {
		if (n < k || n < 0 || k < 0) return 0;
		return fact_[n] * finv_[k] * finv_[n-k];
	}
	constexpr T P(int n, int k) const noexcept {
		if (n < k || n < 0 || k < 0) return 0;
		return fact_[n] * finv_[n-k];
	}
	constexpr T fact(int n) const noexcept {
		if (n < 0) return 0;
		return fact_[n];
	}
	constexpr T inv(int n) const noexcept {
		if (n < 0) return 0;
		return inv_[n];
	}
	constexpr T finv(int n) const noexcept {
		if (n < 0) return 0;
		return finv_[n];
	}
};
 
const int MOD = 1000000007;
// const int MOD = 998244353;
using mint = Fp<MOD>;
BiCoef<mint> bc;
// bc.init(500050);

signed main(){
	int N, K;
	cin >> N >> K;
	vector<int>p(N), c(N);
	cin >> p >> c;
	REP(i, N) --p[i];

	auto f = [&](int start, int K) -> int {
		int ret = -INF;
		vector<int>visit(N);
		{
			auto dfs = [&](auto&&f, int now) -> void {
				if(++visit[now] == 3) {
					return;
				}
				f(f, p[now]);
			};
			dfs(dfs, start);
		}
		vector<int>noLoop;
		vector<int>loop;
		vector<int>used(N);
		{
			auto dfs = [&](auto&&f, int now) -> void {
				if(used[now]) return;
				++used[now];
				if(visit[now] == 1) noLoop.emplace_back(now);
				else loop.emplace_back(now);
				f(f, p[now]);
			};
			dfs(dfs, start);
		}
		int noLoopSum = 0;
		for(auto e: noLoop) noLoopSum += c[e];
		int loopSum = 0;
		for(auto e: loop) loopSum += c[e];
		int acc = 0;
		//if(noLoop.size()) acc -= c[noLoop[0]];
		//else acc -= c[loop[0]];
		REP(i, min(K, (int)noLoop.size())) {
			acc += c[noLoop[i]];
			//if(i)CHMAX(ret, acc);
			CHMAX(ret, acc);
		}
		K -= noLoop.size();
		if(K <= 0) return ret;

		REP(i, min(K, (int)loop.size())) {
			acc += c[loop[i]];
			//if(noLoop.size() || i)CHMAX(ret, acc);
			CHMAX(ret, acc);
		}
		if(K < loop.size()) return ret;
		if(loopSum <= 0) return ret;
		int around = K / loop.size();
		int maxLoop = K - loop.size() * (around - 1);
		int maxSum = noLoopSum + loopSum * (around - 1);
		//if(noLoop.size()) maxSum -= c[noLoop[0]];
		//else maxSum -= c[loop[0]];
		CHMAX(ret, maxSum);
		//out("aaa", start, maxLoop);
		REP(i, maxLoop) {
			maxSum += c[loop[i % loop.size()]];
			CHMAX(ret, maxSum);
		}
		return ret;
	};
	int ans = -INF;
	REP(i, N) {
		int t = f(p[i], K);
		//out(i, t);
		CHMAX(ans, t);
	}
	out(ans);
}

Measured memory_bytes: 4088