#include <bits/stdc++.h>
#define ls rt<<1
#define rs rt<<1|1
using namespace std;

typedef  long long ll;
const ll inf = 0x3f3f3f3f3f3f3f3f;
const int maxn = 1000001;

int n;
struct node {
    int id;
    ll t;
    friend bool operator<(node s1, node s2) {
        return s1.t < s2.t;
    }
} q[2010];
ll a[2010];
ll tr[2010<<2], lz[2010<<2];
void build(int rt, int l, int r) {
    lz[rt] = 0;
    if(l == r) {
        tr[rt] = a[l];
        return ;
    }
    int mid = (l + r) >> 1;
    build(ls, l, mid);
    build(rs, mid + 1, r);
    tr[rt] = min(tr[ls], tr[rs]);
}
ll query(int rt, int l, int r, int L, int R) {
    if(L <= l && R >= r) return tr[rt];
    if(lz[rt]) {
        tr[ls] -= lz[rt], tr[rs] -= lz[rt];
        lz[ls] += lz[rt], lz[rs] += lz[rt];
        lz[rt] = 0;
    }
    int mid = (l + r) >> 1;
    ll ans = inf;
    if(L <= mid) ans = min(ans, query(ls, l, mid, L, R));
    if(R > mid) ans = min(ans, query(rs, mid + 1, r, L, R));
    return ans;
}
void add(int rt, int l, int r, int L, int R, ll u) {
    if(L <= l && R >= r) {
        tr[rt] -= u;
        lz[rt] += u;
        return ;
    }
    if(lz[rt]) {
        tr[ls] -= lz[rt], tr[rs] -= lz[rt];
        lz[ls] += lz[rt], lz[rs] += lz[rt];
        lz[rt] = 0;
    }
    int mid = (l + r) >> 1;
    if(L <= mid) add(ls, l, mid, L, R, u);
    if(R > mid) add(rs, mid + 1, r, L, R, u);
    tr[rt] = min(tr[ls], tr[rs]);
}
int main() {
    int t;
    scanf("%d", &t);
    while(t--) {
        scanf("%d", &n);
        for(int i = 1; i <= n; i++) scanf("%lld", &q[i].t), q[i].id = i;
        for(int i = 1; i <= n; i++)  scanf("%lld", &a[i]), a[i] += a[i - 1];
        build(1, 1, n);
        sort(q + 1, q + 1 + n);

        int ans = 0;
        for(int i = 1; i <= n; i++) {
            ll cost = query(1, 1, n, q[i].id, n);
            if(cost >= q[i].t) {
                ans++;
                add(1, 1, n, q[i].id, n, q[i].t);
            }
        }
        printf("%d\n", ans);
    }
}