import java.io.*; 
import java.math.*;
import java.util.*;
public class Main {  //~IQEmperor~ 
	/*Pause, Hand gestures*/
	/*1 2 4 1 2 4 1 2 4
	 *Final Index: (K)%size (in 0 based indexing)  
	 *K-=Final Index;
	 *Cycles=K/(cycle length)
	 *sum+=Cycles*(sum of cycle) --> If sum of cycle > 0 (sum = elements starting from C[0])
	 *then for loop over [0-Final Index] and maximize answer
	 * 
	 * 
	 *1000 -1 -1
	 *
	 *Sum = -1, -2, 998  
	 * */
	public static void main(String[] args) {
		FastScanner I = new FastScanner(); //Input
		OutPut O = new OutPut(); //Output
		int N = I.nextInt();
		long K = I.nextLong();
		int[] P = new int[N+1];
		long[] C = new long[N+1];
		long ans = Long.MIN_VALUE;
		ArrayList<Integer>[] seqs = new ArrayList[N+1]; //seqs[i] = Cycle you 
		for (int i = 1; i <= N; i++) seqs[i] = new ArrayList<Integer>();
		//follow when you pick square i to start
		for (int i = 1; i <= N; i++) P[i] = I.nextInt();
		for (int i = 1; i <= N; i++) C[i] = I.nextLong();
		for (int i = 1; i <= N; i++) {
			seqs[i].add(i); ///starting point
			boolean[] vis = new boolean[N+1];
			int cur = P[i];
			vis[i]=true;
			while (true) {
				if (vis[cur]) break;
				seqs[i].add(cur);
				cur=P[cur];
			}
		}
		for (int start = 1; start<=N; start++) { //Don't always have to take full cycle 
			//even if sum is > 00
			long sum = 0;
			long curans = 0;
			int in = (int)(K%seqs[start].size());
			long cycles = K/seqs[start].size();
			for (int j = 0; j < seqs[start].size(); j++) {
				int next = seqs[start].get(j);
				sum+=C[next];
			}
			if (sum>0) {
				 cycles--;
				 cycles=max(cycles,0); //For last cycle, 
				 //simply taking everything might back fire
				 long tempK = K-cycles*seqs[start].size();
				 curans = cycles*sum;
				 ans=max(ans,curans);
				 for (int j = 1; j < min(seqs[start].size()*2,tempK+1); j++) {
					 int ind = j%seqs[start].size();
					 int next = seqs[start].get(ind);
					 curans+=C[next];
					 ans=max(ans,curans);
				 }
			}else {
				for (int i = 1; i < min(seqs[start].size()*2,K+1); i++) {
					//If K=1 loop wouldn't process anything
					int ind = i%seqs[start].size();
					int next = seqs[start].get(ind);
					curans+=C[next];
					ans=max(ans,curans);
				}
			}
		}
		O.pln(ans);
		//O.pln("ZERO");
	}
	public static long min(long a, long b) {return Math.min(a,b);}
	public static long max(long a, long b) {return Math.max(a,b);}
	public static int min(int a, int b) {return Math.min(a,b);}
	public static int max(int a, int b) {return Math.max(a,b);}
	public static long abs(long x, long y) {return Math.abs(x-y);}
	public static long ceil(long num, long den) {long ans = num/den; if (num%den!=0) 
	ans++; return ans;}
	public static long GCD(long a, long b) {
		if (a==0||b==0) return Math.max(a,b);
		return GCD(Math.min(a, b),Math.max(a, b)%Math.min(a, b));
	}
	public static long FastExp(long base, long exp, long mod) {
		long ans=1;
		while (exp>0) {
			if (exp%2==1) ans*=base;
			exp/=2;
			base*=base;
			base%=mod;
			ans%=mod;
		}
		return ans;
	}
	public static long ModInv(long num,long mod) {return FastExp(num,mod-2,mod);}
	public static int pop(long x) { //Returns number of bits within a number
		int cnt = 0;
		while (x>0) {
			if (x%2==1) cnt++;
			x/=2;
		}
		return cnt;
	}
	static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		int nextInt() {return Integer.parseInt(next());}
		long nextLong() {return Long.parseLong(next());};
		double nextDouble() {return Double.parseDouble(next());}
	}
	static class OutPut{
		PrintWriter w = new PrintWriter(System.out);
		void pln(double x) {w.println(x);w.flush();}
		void pln(boolean x) {w.println(x);w.flush();}
		void pln(int x) {w.println(x);w.flush();}
		void pln(long x) {w.println(x);w.flush();}
		void pln(String x) {w.println(x);w.flush();}
		void pln(char x) {w.println(x);w.flush();}
		void pln(StringBuilder x) {w.println(x);w.flush();}
		void pln(BigInteger x) {w.println(x);w.flush();}
		void p(int x) {w.print(x);w.flush();}
		void p(long x) {w.print(x);w.flush();}
		void p(String x) {w.print(x);w.flush();}
		void p(char x) {w.print(x);w.flush();}
		void p(StringBuilder x) {w.print(x);w.flush();}
		void p(BigInteger x) {w.print(x);w.flush();}
		void p(double x) {w.print(x);w.flush();}
		void p(boolean x) {w.print(x);w.flush();}
	}
}

Measured memory_bytes: 655876