#include<bits/stdc++.h>
using namespace std;using ll=long long;const int M=998244353;const double eps=1e-10;const ll inf=1e17;
struct S
{
	vector<int>fa,cov,ring;
	vector<ll>w,c;
	vector<vector<int>>es;
	vector<vector<ll>>dres,dprem;
	vector<vector<vector<ll>>>dp;//ring_pos/lay_cnt/drop_cnt
	int n,S,rlen;
	void ini()
	{
		fa.resize(n+1);w.resize(n+1);c.resize(n+1);es.resize(n+1);cov.resize(n+1,0);
		dres.resize(n+1,vector<ll>(n+1));dprem.resize(n+1,vector<ll>(n+1));
	}
	void findring()
	{
		int x,cnt=n+10;
		for(x=fa[S];cnt&&x!=S;x=fa[x],cnt--)ring.push_back(x);	
		if(n==5000&&0)
		{
			cout<<"siz:"<<int(ring.size())<<'|';
			cout<<ring[0]<<"?"<<ring.back()<<'\n';
			cout<<S<<"&"<<x<<'\n';
			int tc=0;
			for(auto k:ring)
			{
				cout<<k<<'_';tc++;
				if(tc%40==0)cout<<'\n';
			}
		}
		if(cnt==-1)ring.clear();ring.push_back(x);reverse(ring.begin(),ring.end());
	}
	void spr(int x)
	{
		for(int i=0;i<=n;i++)dres[x][i]=w[x]*(i&1)-c[x]*i;
		for(auto k:es[x])if(!cov[k]){spr(k);for(int i=0;i<=n;i++)dres[x][i]+=dprem[k][i];}
		dprem[x][0]=0;for(int i=1;i<=n;i++)dprem[x][i]=max(dprem[x][i-1],dres[x][i]);
		//cout<<x<<":val:"<<w[x]<<" cost:"<<c[x]<<" fa:"<<fa[x]<<'\n';
		//cout<<"dres:";for(auto kk:dres[x])cout<<kk<<'_';cout<<'\n';
		//cout<<"dprem:";for(auto kk:dprem[x])cout<<kk<<'_';cout<<'\n';
		//cout<<"***\n";
	}
	void solve()
	{
		cin>>n>>S;ini();for(int i=1;i<=n;i++)cin>>w[i];for(int i=1;i<=n;i++)cin>>c[i];
		for(int i=1;i<=n;i++)cin>>fa[i],es[fa[i]].push_back(i);findring();rlen=ring.size();
		cov.assign(n+1,0);for(auto k:ring)cov[k]=1;
		//for(auto k:ring)cout<<k<<"_";cout<<'\n';
		if(n==5000)return;
		for(auto k:ring)spr(k);
		
		/*
		for(auto k:ring)
		{
			cout<<k<<":\n";
			cout<<"dres:";for(auto kk:dres[k])cout<<kk<<'_';cout<<'\n';
			cout<<"dprem:";for(auto kk:dprem[k])cout<<kk<<'_';cout<<'\n';
		}
		*/

		dp.resize(rlen,vector<vector<ll>>(n+1,vector<ll>(3,-inf)));
		for(int i=0;i<=n;i++)dp[rlen-1][i][0]=dres[ring.back()][i];
		for(int i=rlen-2;i>=0;i--)
		{
			for(int a=0;a<=n;a++)
			{
				for(int b=a;b>=max(0,a-2);b--)
				{
					for(int c=b;c>=max(0,a-2);c--)
					{
						dp[i][a][a-c]=max(dp[i][a][a-c],dp[i+1][b][b-c]);
					}
				}
				for(int e=0;e<3;e++)
				{
					dp[i][a][e]+=dres[ring[i]][a];
					//cout<<i<<'/'<<ring[i]<<":pos"<<a<<" drop:"<<e<<":"<<dp[i][a][e]<<'\n';
				}
			}
		}
		ll res=-inf;
		//if(rlen<=1){cout<<"0\n";return;}
		if(rlen==1)res=dp[0][1][0];
		else if(rlen==2)res=max(dp[0][2][2],max(dp[0][1][0],dp[0][1][1]));
		else for(int i=1;i<=n;i++)for(int e=0;e<3;e++)res=max(res,dp[0][i][e]);
		cout<<res+c[S]<<"\n";
	}
};
void precal()
{

}
int main()
{
	//freopen("1.in","r",stdin);
	//cout<<fixed<<setprecision(12);
	ios::sync_with_stdio(0);cin.tie(0);precal();
	int t=1;//cin>>t;
	//clock_t a=clock();
	while(t--) { S SS;SS.solve(); }
	//cout<<"Time:"<<double(clock()-a)<<'\n';
}