using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using static System.Console;
using static System.Math;
using static Atcoder.IO;

namespace Atcoder
{
    class Program
    {
        static StreamWriter sw = new StreamWriter(OpenStandardOutput()) { AutoFlush = false };
        static void Main(string[] args)
        {
            try
            {
                SetOut(sw);
                Solve.Answer();
                Out.Flush();
            }
            catch (Exception ex)
            {
                WriteLine(ex.ToString());
                Out.Flush();
            }
        }
    }

    public class Solve
    {
        public static void Answer()
        {
            var NK = RSLong;
            var N = NK[0];
            var K = NK[1];
            var P = RSLong;
            var C = RSLong;

            long ans = long.MinValue;
            for (int i = 1; i <= N; i++)
            {
                long cost = 0;
                long cnt = 0;
                long now = i;
                var arrived = new List<long>();
                var has = new HashSet<long>();
                arrived.Add(now);
                has.Add(now);

                while (true)
                {
                    cnt++;
                    now = P[now - 1];
                    cost += C[now - 1];
                    ans = Max(ans, cost);

                    arrived.Add(now);
                    if (!has.Add(now))
                    {
                        long preCost = 0;
                        for (int j = 0; j < arrived.IndexOf(now); j++)
                        {
                            preCost += C[arrived[j] - 1];
                        }
                        long loopCost = cost - preCost;
                        long rest = K - cnt;
                        long loopLen = arrived.Count - arrived.IndexOf(now) - 1;
                        //cost -= C[now - 1];
                        if (rest / loopLen >= 1)
                        {
                            for (int j = 0; j < loopLen; j++)
                            {
                                cost += C[arrived[j] - 1];
                                ans = Max(ans, cost);
                            }
                            cost += loopCost * ((rest / loopLen) - 2);
                            for (int j = 0; j < loopLen; j++)
                            {
                                cost += C[arrived[j] - 1];
                                ans = Max(ans, cost);
                            }
                            ans = Max(ans, cost);
                        }
                        for (int j = 0; j < rest % loopLen; j++)
                        {
                            cost += C[arrived[j] - 1];
                            ans = Max(ans, cost);
                        }
                        break;
                    }
                    if (cnt == K) break;
                }
            }
            WriteLine(ans);
        }
    }

    public class IO
    {
        #region Input
        public static int RInt => int.Parse(ReadLine());
        public static long RLong => long.Parse(ReadLine());
        public static double RDouble => double.Parse(ReadLine());

        public static string[] RSString => ReadLine().Split();
        public static int[] RSInt => ReadLine().Split().Select(s => int.Parse(s)).ToArray();
        public static long[] RSLong => ReadLine().Split().Select(s => long.Parse(s)).ToArray();
        public static double[] RSDouble => ReadLine().Split().Select(s => double.Parse(s)).ToArray();
        #endregion

        #region Output
        public static void OutJoinSpace<T>(IEnumerable<T> list) => WriteLine(string.Join(" ", list));
        public static void WriteLineYes_or_No(bool flag) => WriteLine(flag ? "Yes" : "No");
        public static void WriteLineYES_or_NO(bool flag) => WriteLine(flag ? "YES" : "NO");
        #endregion
    }

    public class Mod
    {
        #region
        private readonly static long M = 1000000007;

        public static long Add(long a, long b) => (a * b) % M;
        public static long Sub(long a, long b) => (a - b) % M >= 0 ? (a - b) % M : (a - b) % M + M;
        public static long Multi(long a, long b) => (a * b) % M;
        #endregion
    }
}

Measured memory_bytes: 43424