#include <algorithm>
#include <complex>
#include <cstdlib>
#include <ctime>
#include <time.h>
#include <iomanip>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <numeric>
#include <limits>
#include <type_traits>
#include <locale>
#include <omp.h>

using namespace std;
#define SAY_YES cout << "YES" << endl;
#define SAY_Yes cout << "Yes" << endl;
#define SAY_NO cout << "NO" << endl;
#define SAY_No cout << "No" << endl;
#define IFYES(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "YES" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "NO" << endl;  \
    }
#define IFYes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "Yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "No" << endl;  \
    }
#define IFyes(TRUE_OR_FALSE)   \
    if (TRUE_OR_FALSE)         \
    {                          \
        cout << "yes" << endl; \
    }                          \
    else                       \
    {                          \
        cout << "no" << endl;  \
    }
#define DEBUG_OUTPUT_ARRAY(XXX, ONE)                            \
    for (int i = 0; i < (ONE); i++)                             \
    {                                                           \
        cout << "DEBUG: i = " << i << " -> " << XXX[i] << endl; \
    }
#define DEBUG_OUTPUT_ARRAY2(XXX, ONE, TWO)                             \
    for (int i = 0; i < (ONE); i++)                                    \
    {                                                                  \
        cout << "<<< i = " << i << " >>>" << endl;                     \
        for (int j = 0; j < (TWO); j++)                                \
        {                                                              \
            cout << "DEBUG: j = " << j << " -> " << XXX[i][j] << endl; \
        }                                                              \
    }
#define DEBUG_OUTPUT_ARRAY2_BOX(XXX, ONE, TWO) \
    for (int i = 0; i < (ONE); i++)            \
    {                                          \
        cout << i << "  ";                     \
        for (int j = 0; j < (TWO); j++)        \
        {                                      \
            cout << XXX[i][j] << " ";          \
        }                                      \
        cout << endl;                          \
    }

typedef pair<long long int, long long int> pll;
typedef pair<long long int, pll> lpll;

const long long int mod = 1000000007;
const long long int INF = 1e18;
const long double PI=3.14159265358979323; 
//const long long int pl=1000000;
long long int N,Q,X,D,res=-INF,K=0,L[500200],P[6000],C[6000];
string S;
pll used[5500]={};




int main(){

    cout << fixed << setprecision(18);
    cin>>N>>K;
    for(long long int i = 0; i < N; i++){
        cin>>P[i];
        P[i]--;
    }
    for(long long int i = 0; i < N; i++){
        cin>>C[i];
        
    }
    for(long long int i = 0; i < N; i++){
        for(long long int j = 0; j < N; j++){
            used[j]={-1,-1};
        }
        long long int now=i,nowpt=0,restmp=-INF;
        used[i]={0,0};
        for(long long int j = 1; j <= min(K,N); j++){
            
            //cout<<i<<" "<<j<<" "<<nowpt<<endl;
            now=P[now];
            nowpt+=C[now];
            restmp=max(restmp,nowpt);
            if(used[now].first!=-1){
                if(used[now].second<nowpt){
                    if(((K-j)/(j-used[now].first))>=1){
                        //cout<<"Type1 "<<used[now].first<<endl;
                        //cout<<"Type1_2 "<<(nowpt)<<" "<<(j-used[now].first)<<endl;
                        nowpt+=(nowpt-used[now].second)*((K-j)/(j-used[now].first)-1);
                        
                        long long int nokori=(K-j)%(j-used[now].first)+(j-used[now].first);
                        for(long long int k = 1; k <= nokori; k++){
                            now=P[now];
                            nowpt+=C[now];
                            restmp=max(restmp,nowpt);
                        }
                        
                    }else{
                        //cout<<"Type2"<<endl;
                        for(long long int k = 1; k <= K-j; k++){
                            now=P[now];
                            nowpt+=C[now];
                            restmp=max(restmp,nowpt);
                        }
                    }
                    break;
                }
                
            }
            used[now]={j,nowpt};
            //cout<<i<<" "<<j<<" "<<nowpt<<endl;
        }
        res=max(restmp,res);

    }
    cout<<res<<endl;
}



Measured memory_bytes: 3804