#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> slots, users;
for (int i = 0, x; i < n; ++i) {
cin >> x;
for (int j = 0; j < x; ++j) {
slots.push_back(i);
}
}
for (int i = 0, x; i < n; ++i) {
cin >> x;
for (int j = 0; j < x; ++j) {
users.push_back(i);
}
}
int ans = -inf;
for (int discard = 0; discard <= users.size(); ++discard) {
deque<int> dq(users.begin(), users.end());
for (int i = 0; i < discard && !dq.empty(); ++i) {
dq.pop_front();
}
int cur = -discard;
for (int i = 0; i < dq.size(); ++i) {
cur += (slots[i] < dq[i]) - (slots[i] > dq[i]);
}
ans = max(ans, cur);
}
cout << ans << '\n';
}
