#define _CRT_SECURE_NO_WARNINGS
#define _SCL_SECURE_NO_WARNINGS
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <utility>
#include <algorithm>
#include <functional>
#include <cmath>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <iomanip>
#include <sstream>
#include <bitset>
#include <limits>
#include <numeric>
#include <valarray>
#include <fstream>
#include <array>
#include <random>
#include <unordered_set>
#include <unordered_map>

using namespace std;
using uint = uint32_t;
using LL = int64_t;
using ULL = uint64_t;
using PP = pair<LL, LL>;
template <typename T> using PriorityQ = priority_queue<T, vector<T>, greater<T> >;
#define REP(i, a, n) for(LL i = (a), i##_max_ = (n); i < i##_max_; ++i)
#define REM(i, a, n) for(LL i = (LL)(n) - 1, i##_min_ = (a); i >= i##_min_; --i)
#define FLOAT fixed << setprecision(16)
#define SPEEDUP { cin.tie(NULL); ios::sync_with_stdio(false); }
const int INF = 0x3FFFFFFF;
const LL INFLL = 0x3FFFFFFF3FFFFFFF;
const double INFD = 1.0e+308;
const double EPS = 1.0e-9;

void YesNo(bool b) { cout << (b ? "Yes" : "No") << endl; }
void YESNO(bool b) { cout << (b ? "YES" : "NO") << endl; }
template <class T, class U> istream& operator>>(istream& ist, pair<T, U>& right) { return ist >> right.first >> right.second; }
template <class T, class U> ostream& operator<<(ostream& ost, const pair<T, U>& right) { return ost << right.first << ' ' << right.second; }
template <class T, class TCompatible, size_t N> void Fill(T(&dest)[N], const TCompatible& val) { fill(dest, dest + N, val); }
template <class T, class TCompatible, size_t M, size_t N> void Fill(T(&dest)[M][N], const TCompatible& val) { for (int i = 0; i < M; ++i) Fill(dest[i], val); }
template <class T> T Next() { T buf; cin >> buf; return buf; }
istream& Ignore(istream& ist) { string s; ist >> s; return ist; }
bool Inside(int i, int j, int h, int w) { return i >= 0 && i < h&& j >= 0 && j < w; }

#ifdef ONLY_MY_ENVIR
#include "Accumulator.h"
#include "Algebraic.h"
#include "BinaryMatrix.h"
#include "BinaryTree.h"
#include "Bipartite.h"
#include "BIT.h"
#include "Compressor.h"
#include "Decompositions.h"
#include "DiscreteLog.h"
#include "DynamicMod.h"
#include "Exponential.h"
#include "Factorization.h"
#include "FFT.h"
#include "FlowSolver.h"
#include "Geometric2D.h"
#include "Geometric2DFloat.h"
#include "Geometric3D.h"
#include "Geometric3DFloat.h"
#include "Graph.h"
#include "GraphUtil.h"
#include "Interpolation.h"
#include "IntMod.h"
#include "KDTree.h"
#include "LazySegmentTree.h"
#include "LIS.h"
#include "List.h"
#include "Math.h"
#include "MathUtil.h"
#include "Matrix.h"
#include "MinCostFlowSolver.h"
#include "MinMax.h"
#include "Numbers.h"
#include "Optimize.h"
#include "Permutation.h"
#include "Polynomial.h"
#include "Position.h"
#include "Random.h"
#include "Range.h"
#include "Rational.h"
#include "RollingHash.h"
#include "RuntimeMod.h"
#include "SegmentTree.h"
#include "SegmentTree2D.h"
#include "Sets.h"
#include "Shortest.h"
#include "SlidingWindow.h"
#include "SpanningTree.h"
#include "StringSearching.h"
#include "SuffixArray.h"
#include "SwitchList.h"
#include "Timer.h"
#include "Tree.h"
#include "TreeUtil.h"
#include "UnionFind.h"
#include "Util.h"
#include "VectorUtil.h"
#endif

#ifdef __GNUC__
typedef __int128 LLL;
istream& operator>>(istream& ist, __int128& val) { LL tmp; ist >> tmp; val = tmp; return ist; }
ostream& operator<<(ostream& ost, __int128 val) { LL tmp = val; ost << tmp; return ost; }
#endif

int n;
LL k;
int p[5000];
LL c[5000];

LL sub(int s) {
	vector<LL> cs;
	
	int i = s;
	while (true) {
		i = p[i];
		cs.push_back(c[i]);
		if (i == s) break;
	}

	LL mx = -INFLL;
	LL sum = accumulate(cs.begin(), cs.end(), 0LL);
	LL tmp = 0;
	REP(i, 0, cs.size()) {
		LL rem = (k - i) / cs.size();
		if (i <= k) {
			LL ans = tmp + (sum > 0 ? rem * sum : 0);
			mx = max(mx, ans);
		}
		tmp += cs[i];
	}
	return mx;
}

int main() {
	cin >> n >> k;
	REP(i, 0, n) {
		cin >> p[i];
		--p[i];
	}
	REP(i, 0, n) cin >> c[i];

	{
		bool neg = true;
		REP(i, 0, n) {
			if (c[i] > 0) {
				neg = false;
			}
		}
		if (neg) {
			cout << *max_element(c, c + n) << endl;
			return 0;
		}
	}

	
	LL mx = -INFLL;
	REP(i, 0, n) {
		mx = max(mx, sub(i));
	}
	cout << mx << endl;
	return 0;
}


Measured memory_bytes: 3788