RT

#include<iostream>
#include<algorithm>
typedef long long Int;
constexpr int MAXN = 1000000;
constexpr int MAXW = 1000000;
int N, M, F[1 + MAXN], W[1 + MAXW], last[1 + MAXN] {}, lastlast[1 + MAXN] {};
enum OPTTYPE{
	GETS, GETL, GETR, GETA
};
// 此题为单点修改，区间查询最大子段和 
struct Seg{
	int L, R;
	Seg *ls, *rs;
	Int sum, lmax, rmax, amax;
	Seg (){
		sum = lmax = rmax = amax = 0;
	}
} sentry;
void build_tree(Seg *root, int L, int R){
	root->L = L, root->R = R;
	if (R - L <= 1){
		return ;
	}
	root->ls = new Seg, root->rs = new Seg;
	int mid = (L + R) >> 1;
	build_tree(root->ls, L, mid);
	build_tree(root->rs, mid, R);
}
void change(Seg *root, int pos, int X){
	if (pos == 0) return ;
	if (root->R - root->L <= 1){
		root->sum = X;
		root->lmax = X;
		root->rmax = X;
		root->amax = X;
		return ;
	}
	if (pos < root->ls->R){
		change(root->ls, pos, X); 
	} else if (pos >= root->rs->L){
		change(root->rs, pos, X);
	}
	root->sum = root->ls->sum + root->rs->sum,
	root->lmax = std:: max(root->ls->lmax, root->ls->sum + root->rs->lmax);
	root->rmax = std:: max(root->ls->rmax + root->rs->sum, root->rs->rmax);
	root->amax = std:: max(root->ls->rmax + root->rs->lmax, std:: max(root->ls->amax, root->rs->amax));
}
Int query(Seg *root, int R, char what){
	if (root->R <= R){
		if (what == OPTTYPE::GETS) return root->sum;
		if (what == OPTTYPE::GETL) return root->lmax;
		if (what == OPTTYPE::GETR) return root->rmax;
		if (what == OPTTYPE::GETA) return root->amax;
	}
	if (root->rs->L < R){
		if (what == OPTTYPE::GETS) return root->ls->sum + root->rs->sum;
		if (what == OPTTYPE::GETL) return std:: max(root->ls->lmax, root->ls->sum + root->rs->lmax);
		if (what == OPTTYPE::GETR) return std:: max(root->ls->rmax + root->rs->sum, root->rs->rmax);
		if (what == OPTTYPE::GETA) return std:: max(root->ls->rmax + root->rs->lmax,std:: max(root->ls->amax, root->rs->amax));
	} else {
		if (what == OPTTYPE::GETS) return root->ls->sum;
		if (what == OPTTYPE::GETL) return root->ls->lmax;
		if (what == OPTTYPE::GETR) return root->ls->rmax;
		if (what == OPTTYPE::GETA) return root->ls->amax;
	}
}
int main(){
	std:: ios:: sync_with_stdio(false);
	std:: cin >> N >> M;
	for (int i = 1 ; i <= N ; i++){
		std:: cin >> F[i];
	}
	for (int i = 1 ; i <= M ; i++){
		std:: cin >> W[i];
	}
	build_tree(&sentry, 1, N + 1);
	Int ans = 0;
	for (int i = 1 ; i <= N ; i++){
		change(&sentry, i, W[F[i]]);
		change(&sentry, last[F[i]], -W[F[i]]);
		change(&sentry, lastlast[F[i]], 0);
		lastlast[F[i]] = last[F[i]];
		last[F[i]] = i;
		ans = std:: max(ans, query(&sentry, i + 1, OPTTYPE::GETA));
	}
	std:: cout << ans << '\n';
	return 0;
}