#include<bits/stdc++.h>
#define pii pair<int,int>
#define ll long long int
#define f first
#define s second
using namespace std;const ll identity = -10000000000; ll dp[3000005];
ll tree[12*100000];
void update(int s,int e,int idx,int node,ll val){
	if(s>idx||e<idx)
	return;
	if(s==e){
		tree[node]=val;
		dp[idx]=val;
		return ;
	}
	ll m=s+e;
	m=m>>1;
	if(idx>=s&&idx<=m){update(s,m,idx, 2*node,val);


	}
	if(idx<=e&&idx>m){
		update(m+1,e,idx,2*node+1,val);
	}
	tree[node]=max(tree[2*node],tree[2*node+1]);
}
ll query(int s,int e,int l,int r,int node){
		if(s>r||e<l)
	return identity;
	if(s>=l&&e<=r){

		return tree[node];
	}
	ll m=s+e;
	m=m>>1;
	ll p1=query(s,m,l,r,2*node);
	ll p2=query(m+1,e,l,r,2*node+1);
return max(p1,p2);

}ll n,h[3000000],b[3000000],ind[3000000];
int main(){
	cin>>n;
	for(int i=0;i<n;i++){
		cin>>h[i];
		dp[i]=identity;
	}
	for(int i=0;i<3*n;i++){
		tree[i]=identity;
	}
	for(int i=0;i<n;i++){
		cin>>b[i];	dp[i]=identity;
	}
	dp[0]=b[0];
	stack<pii> S;
	for(int i=0;i<n;i++){
		while(!S.empty()&& S.top().f>=h[i]){
			S.pop();
		}

		if(i!=0){
		if(!S.empty())
	{
	ll x=query(0,n-1,S.top().s,i,1);

	dp[i]=max(dp[i],x+b[i]);
	dp[i]=max(dp[i],dp[S.top().s-1]+b[S.top().s]);
	dp[i]=max(dp[i],dp[S.top().s]);
	}
	else{
		ll x=query(0,n-1,0,i,1);
		dp[i]=max(dp[i],x+b[i]);
		dp[i]=max(dp[i],b[i]);
	}
		}
		update(0,n-1,i, 1,dp[i]);
		S.push({h[i],i});

	}

	cout<<dp[n-1];
	return 0;
}