#include<bits/stdc++.h>
using namespace std;
using ll = long long;
//using LL = __int128
#pragma GCC optimize(2)
#define pi pair<ll, ll>
#define N 1111111
ll n, t[N], a[N], b[N], dp[N];
vector<pi> g[N];
int main(){
	scanf("%lld", &n);
	for(int i = 1 ; i <= n ; i++){
		scanf("%lld", &t[i]);
	}
	for(int i = 1 ; i <= n ; i++){
		scanf("%lld", &a[i]);
		b[i] = a[i] * t[i];
		t[i] = min(t[i], n);
		if(i + t[i] <= n)
			g[i + t[i]].push_back({i, t[i]});
	}
	if(n <= 5000){
		for(int i = 1 ; i <= n ; i++){
			dp[i] = b[i];
			for(int j = 0 ; j < i ; j++)
				if(i - j >= max(t[i], t[j]))
					dp[i] = max(dp[i], b[i] + dp[j]);
			//cerr << dp[i] << " \n"[i == n];
		}
		printf("%lld", *max_element(dp + 1 , dp + 1 + n));
		return 0;
	}
	return 0;
}