#pragma GCC optimize ("O3")
#pragma GCC target ("avx2")

#include <stack>
#include <queue>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <map>
#include <set>
#include <tuple>
#include <cmath>
#include <random>
#include <algorithm>
#include <vector>
#include <iostream>
#include <fstream>
#include <chrono>
#include <numeric>

#define fio ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr)
#define rng mt19937_64 rnd(chrono::system_clock::now().time_since_epoch().count())

#define ri(...) i64 __VA_ARGS__; rx(__VA_ARGS__)
#define rc(...) char __VA_ARGS__; rx(__VA_ARGS__)
#define rs(...) string __VA_ARGS__; rx(__VA_ARGS__)
#define rvi(x, n) vi x(n); cin >> x
#define rvvi(x, n, m) vvi x(n, vi(m)); cin >> x

#ifndef ONLINE_JUDGE
#define dbg(...) cerr << '[' << #__VA_ARGS__ << "]: "; dbg_log(__VA_ARGS__)
#else
#define dbg(...) ;;
#endif

#define fa(i, v) for (auto &i : v)
#define fi(i, n) for (i32 i = 0; i < n; i++)
#define fp(i, n) for (i32 i = 1; i < n; i++)
#define fr(i, n) for (i32 i = n - 1; i >= 0; i--)
#define fu(i) ri(_i); fi(i, _i)

#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()

using namespace std;

typedef uint32_t u32;
typedef int32_t i32;
typedef uint64_t u64;
typedef int64_t i64;
#ifdef __SIZEOF_INT128__
typedef __uint128_t u128;
typedef __int128_t i128;
#endif
typedef vector<i64> vi;
typedef vector<vi> vvi;

template<typename T>
inline istream &operator>>(istream &in, vector<T> &v) {
    fa(x, v) in >> x;
    return in;
}

template<typename T>
inline ostream &operator<<(ostream &out, const vector<T> &v) {
    fa(x, v) out << x << ' ';
    return out;
}

template<typename T>
inline void rx(T &x) {
    cin >> x;
}

template<typename T, typename... R>
inline void rx(T &x, R &... l) {
    cin >> x;
    rx(l...);
}

template<typename T>
inline void dbg_log(const T &x) {
    cerr << x << '\n';
}

template<typename T, typename... R>
inline void dbg_log(const T &x, const R &... l) {
    cerr << x << ", ";
    dbg_log(l...);
}

template<typename T>
inline void wl(const T &x) {
    cout << x << '\n';
}

template<typename T, typename... R>
inline void wl(const T &x, const R &... l) {
    cout << x << ' ';
    wl<R...>(l...);
}

int main() {
    fio;

    ri(n, k);
    rvi(p, n);
    rvi(c, n);

    vector<bool> visited(n);
    vi buf;
    vi mem;
    i64 best = numeric_limits<i64>::min();
    fi(t, n) {
        {
            buf.clear();
            i32 s = t;
            while (!visited[s]) {
                visited[s] = true;
                buf.push_back(s);
                s = p[s] - 1;
            }
            if (buf.empty()) continue;
        }

        i64 res = 0;
        i64 total = 0;
        fa(x, buf) total += c[x];
        i64 u = max(0, (i32) (k / buf.size() - 1));
        if (total > 0) res += u * total;
        i64 v = k - buf.size() * u;

        {
            mem.resize(3 * buf.size() + 1);
            fi(i, 3 * buf.size()) {
                mem[i + 1] = mem[i] + c[buf[i % buf.size()]];
            }
        }

        i64 mx = numeric_limits<i64>::min();
        fi(i, buf.size()) {
            for (i32 j = 1; j <= v && i + j <= 3 * n; j++) {
                mx = max(mx, mem[i + j] - mem[i]);
            }
        }
        res += mx;

        best = max(best, res);
    }
    wl(best);

    return 0;
}


Measured memory_bytes: 3848