using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace AtCoder2 {
	class Program {
		static void Main(string[] args) {

			//出力の都度更新をやめる
			var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
			Console.SetOut(sw);


			Ans();

			//更新する
			Console.Out.Flush();
			
		}
		public static void Ans() {

			var inputArray = retreiveLongArray();
			var inputCount = 2;

			// 不正な入力は処理しない
			if (inputArray.Length != inputCount) {
				Console.WriteLine("invalid input");
				return;
			}
			long N = inputArray[0];
			long K = inputArray[1];

			var moveArray = retreiveLongArray().Select(x =>x-1).ToArray();
			var scoreArray = retreiveLongArray();

			var loopScore = new List<long>();
			var loopLength= new List<long>();

			var loopContent = new List<List<long>>();
			var used = Enumerable.Repeat(false, (int)N).ToArray();

			for (int i = 0; i < N; i++) {
				if (used[i]) {
					continue;
				}
				var loop = new List<long>();

				long score = 0;
				var length = 0;
				loop.Add(i);
				used[i] = true;
				long current = i;
				while (true) {
					var next = moveArray[current];
					score += scoreArray[next];
					length++;
					if (used[next]) {
						break;
					}
					loop.Add(next);
					used[next] = true;
					current = next;
				}
				loopScore.Add(score);
				loopLength.Add(length);
				loopContent.Add(loop);
			}
			long max = scoreArray.Min();
			
			//ループごとに最大値を求める
			for (int i = 0; i < loopScore.Count(); i++) {
				var loop = loopContent[i];
				var length = loopLength[i];
				var isshuScore = loopScore[i];
				if (K < length) {
					var remain = K;
					if (remain == 0) {//余りが存在しない場合
						continue;
					}
					long remainMax = scoreArray.Min();
					for (int j = 0; j < length; j++) {
						long remScore = 0;
						var current = loop[j];
						for (int k = 0; k < remain; k++) {
							var next = moveArray[current];
							remScore += scoreArray[next];
							current = next;
							remainMax = Math.Max(remScore, remainMax);
						}

					}
					var finalScore =remainMax;
					max = Math.Max(max, finalScore);
				}
				else {
					var roopnum = (K / length)-1;
					var score = Math.Max(roopnum * isshuScore, 0);

					//最後の1週+あまりについて検証する
					var remain = isshuScore <= 0 ? length : K % length+length;

					long remainMax = scoreArray.Min();
					for (int j = 0; j < length; j++) {
						long remScore = 0;
						var current = loop[j];
						for (int k = 0; k < remain; k++) {
							var next = moveArray[current];
							remScore += scoreArray[next];
							current = next;
							remainMax = Math.Max(remScore, remainMax);
						}

					}
					var finalScore = score + remainMax;
					max = Math.Max(max, finalScore);
				}

			}

			//答えの出力
			var ans = max;
			Console.WriteLine(ans);

		}

		/// <summary>
		/// スペースで区切られた文字列配列の入力を受け取る
		/// </summary>
		/// <returns></returns>
		private static string[] retreiveStringArray() {
			var inputArray = Console.ReadLine().Split(' ');
			return inputArray;
		}

		/// <summary>
		/// スペースで区切られた整数配列の入力を受け取る
		/// </summary>
		/// <returns></returns>
		private static long[] retreiveLongArray() {
			var inputArray = Console.ReadLine().Split(' ');
			var longArray = inputArray.Select(s => long.Parse(s));
			return longArray.ToArray();
		}


		/// <summary>
		/// 2組みずつの入力データ(数値)からTuppleListを作成する
		/// </summary>
		/// <param name="N"></param>
		/// <returns></returns>
		private static List<Tuple<long, long>> createLongTuppleList(long N) {
			var inpList = new List<Tuple<long, long>>();

			for (int i = 0; i < N; i++) {
				var inp = retreiveLongArray();
				var item1 = inp[0];
				var item2 = inp[1];
				inpList.Add(new Tuple<long, long>(item1, item2));
			}
			return inpList;
		}
	}
}


Measured memory_bytes: 29808