#include<cmath>

#include<queue>

#include<cstdio>

#include<cctype>

#include<cstring>

#include<iostream>

#include<algorithm>

using namespace std;

typedef long long ll;

const int N=;

inline int read(){

    int X=,w=;char ch=;

    while(!isdigit(ch)){w|=ch=='-';ch=getchar();}

    while(isdigit(ch))X=(X<<)+(X<<)+(ch^),ch=getchar();

    return w?-X:X;

}

int n,m,f[N],w[N],nxt[N],head[N];

ll tr[N*],lz[N*];

inline void add(int u,int cnt){

    nxt[cnt]=head[u];head[u]=cnt;

}

inline void push(int a){

    if(!lz[a])return;

    lz[a<<]+=lz[a];lz[a<<|]+=lz[a];

    tr[a<<]+=lz[a];tr[a<<|]+=lz[a];

    lz[a]=;

}

void mdy(int a,int l,int r,int l1,int r1,int w){

    if(r<l1||r1<l)return;

    if(l1<=l&&r<=r1){

    tr[a]+=w;lz[a]+=w;

    return;

    }

    push(a);

    int mid=(l+r)>>;

    mdy(a<<,l,mid,l1,r1,w);mdy(a<<|,mid+,r,l1,r1,w);

    tr[a]=max(tr[a<<],tr[a<<|]);

}

int main(){

    n=read(),m=read();

    for(int i=;i<=n;i++)f[i]=read();

    for(int i=;i<=m;i++)w[i]=read();

    for(int i=n;i>=;i--)add(f[i],i);

    for(int i=;i<=m;i++){

    if(head[i]){

        if(!nxt[head[i]])mdy(,,n,head[i],n,w[i]);

        else mdy(,,n,head[i],nxt[head[i]]-,w[i]);

    }

    }

    ll ans=;

    for(int i=;i<=n;i++){

    ans=max(ans,tr[]);

    int t=nxt[i];

    if(t){

        mdy(,,n,i,t-,-w[f[i]]);

        if(nxt[t])mdy(,,n,t,nxt[t]-,w[f[i]]);

        else mdy(,,n,t,n,w[f[i]]);

    }else mdy(,,n,i,n,-w[f[i]]);

    }

    printf("%lld\n",ans);

    return ;

}