#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
ll a[2100],b[2100],s[2100];
int main(){
    int test;
    scanf("%d", &test);
    while(test--){
        int n;
        scanf("%d",&n);
        for(int i=0;i<n;i++){
            scanf("%lld",a+i);
        }//printf("n:%d\n",n);
        ll sum=0;
        for(int i=0;i<n;i++){
            scanf("%lld",b+i);
            sum+=b[i];
            s[i]=sum;
        }
        int ans=0;
        multiset<ll> tasks;
        for(int i=n-1;i>=0;i--){
            tasks.insert(a[i]);
            ll cost=b[i];
            while(cost>0&&tasks.size()>0){
                auto iter=tasks.begin();
                ll val=*iter;
                tasks.erase(iter);
                ll use=min(cost,val);
                val-=use;
                cost-=use;
                if(val==0){
                    ans++;
                    //printf("at %d cost %lld\n",i,cost);
                }
                else tasks.insert(val);
            }
        }
        printf("%d\n",ans);
    }
}