#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int n;
ll x[300005];
ll y[300005];
ll total_users = 0;
ll check(ll K) {
ll cur_score = 0;
int t_ptr = 0;
ll x_rem = x[0];
ll skip = K;
for (int s = 0; s < n; s++) {
ll available_y = y[s];
if (skip > 0) {
ll taking = min(skip, available_y);
available_y -= taking;
skip -= taking;
}
if (available_y == 0) continue;
while (available_y > 0 && t_ptr < n) {
if (x_rem == 0) {
t_ptr++;
if (t_ptr < n) x_rem = x[t_ptr];
else break;
continue;
}
ll match = min(available_y, x_rem);
if (t_ptr < s) cur_score += match; // Upvote
else if (t_ptr > s) cur_score -= match; // Downvote
available_y -= match;
x_rem -= match;
}
}
ll to_process = K;
for (int s = 0; s < n && to_process > 0; s++) {
ll available_y = min(y[s], to_process);
to_process -= available_y;
if (available_y == 0) continue;
while (available_y > 0 && t_ptr < n) {
if (x_rem == 0) {
t_ptr++;
if (t_ptr < n) x_rem = x[t_ptr];
else break;
continue;
}
ll match = min(available_y, x_rem);
if (t_ptr < s) cur_score += match;
else if (t_ptr > s) cur_score -= match;
available_y -= match;
x_rem -= match;
}
}
return cur_score;
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
if (!(cin >> n)) return 0;
for (int i = 0; i < n; i++) cin >> x[i];
for (int i = 0; i < n; i++) {
cin >> y[i];
total_users += y[i];
}
ll ans=-1e9;
for( int i=0 ; i<total_users ; i++ ){
ans=max( ans, check(i) );
}
cout << ans << endl;
return 0;
}
