#ifndef AUTO_UTIL_HEADER_HPP
#define AUTO_UTIL_HEADER_HPP

#include <bits/stdc++.h>
#include <cassert>

using std::cin, std::cout, std::bitset, std::complex;
using std::vector, std::array, std::string, std::pair, std::list, std::queue, std::deque;
using std::priority_queue, std::set, std::map, std::unordered_map;
using std::sort, std::greater, std::min, std::max, std::reverse;
using std::min_element, std::max_element, std::accumulate;

using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>;
using ull = unsigned long long int;
using ll = long long int;
using vll = vector<ll>; using vvll = vector<vll>; using vvvll = vector<vvll>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
using P = pair<int, int>;
using Pll = pair<ll, ll>;
using cdouble = complex<double>;

const double eps = 1e-7;
#define Loop(i, n) for(int i = 0; i < int(n); i++)
#define Loopll(i, n) for(ll i = 0; i < ll(n); i++)
#define Loop1(i, n) for(int i = 1; i <= int(n); i++)
#define Loopll1(i, n) for(ll i = 1; i <= ll(n); i++)
#define Loopr(i, n) for(int i = int(n) - 1; i >= 0; i--)
#define Looprll(i, n) for(ll i = ll(n) - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = int(n); i >= 1; i--)
#define Looprll1(i, n) for(ll i = ll(n); i >= 1; i--)
#define Foreach(buf, container) for(const auto &buf : container)
#define Foreachr(buf, container)  for(const auto &buf : reversed(container))
#define Loopdiag(i, j, h, w, sum) for(int i = ((sum) >= (h) ? (h) - 1 : (sum)), j = (sum) - i; i >= 0 && j < (w); i--, j++)
#define Loopdiagr(i, j, h, w, sum) for(int j = ((sum) >= (w) ? (w) - 1 : (sum)), i = (sum) - j; j >= 0 && i < (h); j--, i++)
#define Loopdiagsym(i, j, h, w, gap) for (int i = ((gap) >= 0 ? (gap) : 0), j = i - (gap); i < (h) && j < (w); i++, j++)
#define Loopdiagsymr(i, j, h, w, gap) for (int i = ((gap) > (h) - (w) - 1 ? (h) - 1 : (w) - 1 + (gap)), j = i - (gap); i >= 0 && j >= 0; i--, j--)
#define Loopitr(itr, container) for(auto itr = container.begin(); itr != container.end(); itr++)
#define quickio() std::ios::sync_with_stdio(false); std::cin.tie(0);
#define bitmanip(m,val) static_cast<bitset<(int)m>>(val)
#define Comp(type_t) bool operator<(const type_t &another) const
#define fst first
#define snd second
bool feq(double x, double y) { return abs(x - y) <= eps; }
bool inrange(ll x, ll t) { return x >= 0 && x < t; }
bool inrange(vll xs, ll t) { Foreach(x, xs) if (!(x >= 0 && x < t)) return false; return true; }
int ceillog2(ll x) { int m = int(log2(x)); return m + ((1LL << m) < x ? 1 : 0); }
int floorlog2(ll x) { int m = int(log2(x)); return m - ((1LL << m) > x ? 1 : 0); }
const string endl = "\n";
template<class T> T reversed(T container) { reverse(container.begin(), container.end()); return container; }
template<class T> void printv(const vector<T> &v) { for (const T &x : v) cout << x << " "; cout << endl; }
template<class T> void printmx(const vector<vector<T>> &mx) { for (const vector<T> &v : mx) printv(v); }
ll rndf(double x) { return (ll)(x + (x >= 0 ? 0.5 : -0.5)); }
ll floorsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (m*  m <= x ? 0 : -1); }
ll ceilsqrt(ll x) { ll m = (ll)sqrt((double)x); return m + (x <= m * m ? 0 : 1); }
ll rnddiv(ll a, ll b) { return (a / b + (a % b * 2 >= b ? 1 : 0)); }
ll ceildiv(ll a, ll b) { return (a / b + (a % b == 0 ? 0 : 1)); }
ll gcd(ll m, ll n) { if (n == 0) return m; else return gcd(n, m % n); }
ll lcm(ll m, ll n) { return ll(m) * ll(n) / gcd(m, n); }

#endif // AUTO_UTIL_HEADER_HPP

//========================================================================//


// ret[i] = a[i] + a[i + 1] + ... (for length times, with looping)
vll loop_vec_accumulate(const vll &a, ll length) {
	int n = a.size();
	vll ret(n, 0);
	if (n == 0) return ret;
	ll p = length / n;
	if (p > 0) {
		Loop(i, n) ret[0] += a[i];
		ret[0] *= p;
	}
	Loop(i, length % n) ret[0] += a[i];
	Loop1(i, n - 1) {
		ret[i] = ret[i - 1] - a[i - 1] + a[(i + length - 1) % n];
	}
	return ret;
}

ll solve(const vll &a, ll k) {
    int n = a.size();
    ll u = max(0LL, k / n - 1);
    ll v = k - u * n;
    vvll accs(n * 2 + 1);
    Loop1(i, n * 2) {
        accs[i] = loop_vec_accumulate(a, i);
    }
    ll acc_max = LLONG_MIN;
    Loop1(i, v) {
        Loop(j, n) {
            acc_max = max(acc_max, accs[i][j]);
        }
    }
    if (accs[n][0] > 0) {
        return accs[n][0] * u + acc_max;
    }
    else {
        return acc_max;
    }
}

int main() {
    int n;
    ll k; 
    cin >> n >> k;
    vi p(n);
    Loop(i, n) {
        cin >> p[i];
        p[i]--;
    }
    vll c(n); Loop(i, n) cin >> c[i];
    //
    vvll a;
    Loop(i, n) {
        if (p[i] == -1) continue;
        int cur = i;
        a.push_back({});
        while (p[cur] != -1) {
            int next = p[cur];
            a.back().push_back(c[next]);
            p[cur] = -1;
            cur = next;
        }
    }
    ll ans = LLONG_MIN;
    for (const auto &b : a) {
        ans = max(ans, solve(b, k));
    }
    cout << ans << endl;
}


Measured memory_bytes: 394512