import java.io.*
import java.util.*
import java.lang.*
import java.lang.Math.*


fun solve() {
    val (N, K) = rd.readIntArray()
    val P = rd.readIntArray().map{ it-1 }
    val C = rd.readLongArray()

    val vis = BooleanArray(N){false}
    val cycle = ArrayList<List<Int>>()
    for (i in 0 until N) {
        if (vis[i]) continue
        vis[i] = true

        val path = ArrayList<Int>()

        path.add(i)
        var next = P[i]
        while (!vis[next]) {
            vis[next] = true
            path.add(next)
            next = P[next]
        }

        cycle.add(path)
    }
    
    var ans = -LINF
    for (i in 0 until N) {
        var ci = 0
        for (j in 0 until cycle.size) {
            if (cycle[j].contains(i)) {
                ci = j
                break
            }
        }

        val ln = cycle[ci].size
        var pos = cycle[ci].indexOf(i)
        val cs = ArrayList<Long>()
        while (cs.size < cycle[ci].size) {
            pos = (pos+1)%ln
            cs.add(C[cycle[ci][pos]])
        }
        
        val cycleSum = cs.sum()

        var sum = 0L
        for (j in 0 until ln) {
            sum += cs[j]
            if (j+1 > K) break
            var scr = sum

            if (cycleSum>0) {
                val loopNum = (K - (j+1))/ln
                scr += cycleSum*loopNum
            }

            ans = max(ans, scr)
        }
    }

    println(ans)
}


//val rd = debug.Reader("abc", "175", "d", "sample-1")
val rd = Reader()


fun main(args: Array<String>) {
    try {
        var exception: Throwable? = null
        val sth = Thread(null, SolveThread(), "solveThread", 128 * 1024 * 1024)
        sth.setUncaughtExceptionHandler { _, e -> exception = e }
        sth.start(); sth.join()
        if (exception != null) throw exception!!
    } catch (e: Exception) { throw e }
}
const val MOD = 1_000_000_007L; const val INF = Int.MAX_VALUE/2; const val LINF = Long.MAX_VALUE/2
val EPS = 1e-9; fun DBLEQ(a: Double, b: Double): Boolean {return abs(a - b) < EPS}
data class IntPair(val first: Int, val second: Int); data class LongPair(val first: Long, val second: Long)
data class To(val idx: Int, val cost: Long)
fun <T>edge(V: Int): Array<ArrayList<T>> { return Array(V){ArrayList<T>()} }
val errPrintln: (Any) -> Unit = { msg -> System.err.println(msg) }
fun rAssert(exp: Boolean, lazyMsg: () -> String = {""}) {
    if (!exp) { val msg = lazyMsg(); errPrintln("EAssert Error: $msg"); throw Error(msg) }
}
fun tAssert(exp: Boolean, lazyMsg: () -> String = {""}) {
    if (!exp) { val msg = lazyMsg(); errPrintln("TAssert Error: $msg"); Thread.sleep(3000) }
}
class SolveThread : Runnable {
    override fun run() { solve() }
}
class Reader {
    private val br = BufferedReader(InputStreamReader(System.`in`))
    val readString: () -> String = { br.readLine() }
    val readInt: () -> Int = { br.readLine().toInt() }
    val readLong: () -> Long = { br.readLine().toLong() }
    val readIntArray: () -> IntArray = { br.readLine().split(' ').map { it.toInt() }.toIntArray() }
    val readLongArray: () -> LongArray = { br.readLine().split(' ').map { it.toLong() }.toLongArray() }
    val readListInt: () -> List<Int> = { br.readLine().split(' ').map { it.toInt() } }
    val readListLong: () -> List<Long> = { br.readLine().split(' ').map { it.toLong() } }
}


Measured memory_bytes: 59592