#include <bits/stdc++.h>
#include <boost/multiprecision/cpp_int.hpp>
using namespace std;
using bint = boost::multiprecision::cpp_int;
using ll = long long;
using pint = pair<int, int>;
using pll = pair<ll, ll>;
#define rep(i,n) for (int i = 0; i < (n); i++)
#define repSE(i,s,n) for (int i = (s); i < (n); i++)
#define rrepSE(i,s,e) for (int i = (s); i > (e); i--)
#define ssort(v) sort(v.begin(), v.end())
#define gsort(v) sort(v.rbegin(), v.rend())
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename T> bool chmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool chmin(T &m, const T q) { if (q < m) {m = q; return true;} else return false; }
#define DEBUG_PRINT(var) std::cout << #var << " = " << var << "\n";

const ll MX = ll(1e18);

int main()
{
    ll n, k;
    cin >> n >> k;
    vector<int> p(n);
    vector<ll> c(n);
    rep(i,n) { cin >> p[i]; p[i] --; }
    rep(i,n) cin >> c[i];
    ll ans = -MX;
    rep(i, n) {
        ll sum = 0;
        int start = i, cur = i;
        cur = p[cur];
        sum += c[cur];
        ll cnt = 1;
        while (cur != start) {
            cur = p[cur];
            sum += c[cur];
            cnt ++;
        }
        cur = start;
        ll cnt2mx = 0;
        ll accum = 0;
        while (true) {
            cnt2mx ++;
            accum += c[cur];
            if (cnt2mx > k) break;
            ll num = (k - cnt2mx) / cnt;
            ll score = accum + max(0ll, sum) * num;
            chmax(ans, score);
            cur = p[cur];
            if (cur == start) break;
        }
        // cout << "i: " << i << ", cnt: " << cnt << ", mx: " << mx << ", sum: " << sum
        //      << ", cnt2mx: " << cnt2mx << endl;
    }
    cout << ans << "\n";
    return 0;
}


Measured memory_bytes: 3680