#include <cstdio>
#include <algorithm>
#include <vector>
#include <cstring>
#include <queue>
using namespace std;

#define LL long long

const int MX = 2000 + 23;

LL A[MX] ,B[MX] ,SB[MX] ,SA[MX];
int vis[MX];

void solve(){
    int n; scanf("%d" ,&n);
    for(int i = 1 ; i <= n ; ++i)
        scanf("%lld" ,A + i) ,SA[i] = SA[i - 1] + A[i];
    for(int i = 1 ; i <= n ; ++i)
        scanf("%lld" ,B + i) ,SB[i] = SB[i - 1] + B[i];
    
    priority_queue<LL> Q;
    LL Time = 0, Ans = 0;
    B[n + 1] = 0 ,SB[n + 1] = 1e18;
    for(int i = 1 ; i <= n ; ++i){
        Time += B[i];

        if(Time >= A[i]){
            Time -= A[i];
            Ans += 1;
            Q.push(A[i]);
        }
        else if(!Q.empty() && Q.top() > A[i]){
            Time += Q.top() - A[i];
            Q.pop();
            Q.push(A[i]);
        }

    }
    printf("%lld\n" ,Ans);
}

int main(){
    int T; scanf("%d" ,&T);
    while(T--) solve();
    return 0;
}