#include<bits/stdc++.h>
using namespace std;
#pragma region Macros
#define ios\
    ios::sync_with_stdio(false);\
    cin.tie(nullptr);
#define VEC(type, name, size)\
    V<type> name(size);\
    IN(name)
#define VVEC(type, name, h, w)\
    VV<type> name(h, V<type>(w));\
    IN(name)
#define INT(...)\
    int __VA_ARGS__;\
    IN(__VA_ARGS__)
#define LL(...)\
    ll __VA_ARGS__;\
    IN(__VA_ARGS__)
#define STR(...)\
    string __VA_ARGS__;\
    IN(__VA_ARGS__)
#define CHAR(...)\
    char __VA_ARGS__;\
    IN(__VA_ARGS__)
#define DOUBLE(...)\
    DOUBLE __VA_ARGS__;\
    IN(__VA_ARGS__)
#define LD(...)\
    LD __VA_ARGS__;\
    IN(__VA_ARGS__)
template <class T> void scan(T &a) { cin >> a; }
template <class T> void scan(vector<T> &a) { for(auto &i : a) scan(i); }
template <class T, class L> void scan(pair<T, L> &p){ scan(p.first); scan(p.second); }
void IN() {}
template <class Head, class... Tail> void IN(Head &head, Tail &... tail) { scan(head); IN(tail...); }
template <class T> inline void print(T x){ cout << x << '\n';}
#define ll long long
#define ld long double
#define FOR(i,l,r) for(ll i=(l);i<(r);++i)
#define REP(i,n) FOR(i,0,n)
#define REPS(i,n) FOR(i,1,n+1)
#define RFOR(i,l,r) for(ll i=(l);i>=(r);--i)
#define RREP(i,n) RFOR(i,n-1,0)
#define RREPS(i,n) RFOR(i,n,1)
#define pb push_back
#define eb emplace_back
#define SZ(x) ((ll)(x).size())
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()
template<class T = ll> using V = vector<T>;
template<class T = ll> using VV = V<V<T>>;
template<class T> inline bool chmin(T& a, T b) {if (a > b) {a = b; return true; }return false; }
template<class T> inline bool chmax(T& a, T b) {if (a < b) {a = b; return true; }return false; }
inline void Yes(bool b = true) {cout << (b ? "Yes" : "No") << '\n';}
inline void YES(bool b = true) {cout << (b ? "YES" : "NO") << '\n';}
inline void err(bool b = true) {if(b) {cout << -1 << '\n'; exit(0);}}
template<class T> inline void fin(bool b = true, T e = 0) {if(b) {cout << e << '\n'; exit(0);}}
template<class T> T Roundup_div(T x, T y) {return (x+(y-1))/y;}
template <typename T> T pow(T a, long long n, T e = 1) {T ret = e; while (n) {if (n & 1) ret *= a; a *= a; n >>= 1; } return ret; }
const ll INF = 1e18;
#pragma endregion

struct UnionFind {
    public:
    vector<int> par;
    UnionFind(int n){
        par=vector<int>(n,-1);
    }
    int root(int x){
        if(par[x]<0)return x;
    return par[x]=root(par[x]);
    }
    bool issame(int x,int y){
        return root(x)==root(y);
    }
    bool merge(int x,int y){
        x=root(x);
        y=root(y);
        if(x==y)return false;
        if(par[x]>par[y])swap(x,y);
        par[x]+=par[y];
        par[y]=x;
        return true;
    }
    int size(int x){
        return -par[root(x)];
    }
};

int main(){
    ios;
    LL(n, k);
    VEC(ll, p, n);
    VEC(ll, c, n);
    REP(i, n) p[i]--;
    UnionFind uf(n);
    REP(i, n) uf.merge(i, p[i]);
    V<> used(n, false);
    ll res = -INF;
    REP(i, n){
        if(used[uf.root(i)]) continue;
        used[uf.root(i)] = true;
        ll t = uf.size(i);
        ll now = i, sum = 0, nk;
        REP(_, t){
            now = p[now];
            sum += c[now];
        }
        if(sum >= 0){
            ll z = max(k / t - 1, 0ll);
            sum *= z;
            nk = k - z * t;
        }
        else nk = min(k, t - 1), sum = 0;
        REP(s, t){
            ll pre = sum;
            now = i;
            REP(_, s) now = p[now];
            REP(j, nk){
                pre += c[now];
                now = p[now];
                chmax(res, pre);
            }
        }
    }
    print(res);
}

Measured memory_bytes: 3776