#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define vi vector<long long>
#define all(x) x.begin(), x.end()
#define endl "\n"
#define pr pair<ll, ll>
#define ff first
#define ss second
void solution();
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
solution();
return 0;
}
const int N = 5e5+10;
pr a[N];
void solution() {
ll n; cin >> n;
for (int i = 0; i < n; i++) cin >> a[i].ff;
for (int i = 0; i < n; i++) cin >> a[i].ss;
priority_queue<ll> q;
ll ans = 0;
ll x = 0;
for (int i = 0; i < n; i++) {
if (a[i].ss >= x) {
x += a[i].ff;
ans++;
q.push(a[i].ff);
} else {
if (q.size() > 0 && a[i].ss >= x-q.top() && a[i].ff <= q.top()) {
x -= q.top();
x += a[i].ff;
q.pop();
q.push(a[i].ff);
}
}
}
cout << ans << endl;
}
