#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int mxN = 300001;
ll x[mxN], y[mxN], X[mxN], Y[mxN];
/*
Claim: The users giving a positive review
must form a subarray of y
Proof:
Take users a < b < c
Such that :
user a took a seat in tier x < a
user b took a seat in tier y > b
user c took a seat in tier z < c
We can get a similar or better score :
user a takes seat still in z
user b takes seat in x
user c takes seat in z
This way, we have +1 from c (c > z)
And we have +1 from b (x < a < b)
And for c it doesnt matter since the situation is similar/better
*/
ll compute(ll l, ll n){
for (ll i=0;i<n;i++) X[i] = x[i], Y[i] = y[i];
ll ans = 0, i = l, j = 0;
while(i<n){
while(i<n && !Y[i]) i++;
while(!X[j]) j++;
if (i == n) break;
ll s;
if (i==j) s=0;
else if (i<j) s=-1;
else s=1;
if (Y[i] <= X[j]){
ans += Y[i] * s;
X[j] -= Y[i];
i++;
} else {
ans += X[j] * s;
Y[i] -= X[j];
j++;
}
}
i = 0;
while(i<l){
while(i<l && !Y[i]) i++;
while(!X[j]) j++;
if (i == l) break;
ll s;
if (i==j) s=0;
else if (i<j) s=-1;
else s=1;
if (Y[i] <= X[j]){
ans += Y[i] * s;
X[j] -= Y[i];
i++;
} else {
ans += X[j] * s;
Y[i] -= X[j];
j++;
}
}
return ans;
}
void solve(){
ll n; cin>>n;
for (ll i=0;i<n;i++) cin>>x[i];
for (ll i=0;i<n;i++) cin>>y[i];
ll ans = -1e18;
for (ll t=0;t<n;t++) ans = max(ans, compute(t, n));
cout << ans << endl;
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
solve();
}
