#include<bits/stdc++.h>
#define ll long long
#define FAST ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
using namespace std;


int main(){

FAST;
int t ;cin>>t;

while(t--){
     int co=0;
    int n,m=0;cin>>n;
    int a[n],b[n];
    for (int i = 0 ; i<n;i++){
        cin>>a[i];
    }
    for (int i =0;i<n;i++){
        cin>>b[i];
    }
    for (int i=0;i<n;i++){
        if(a[i]<=b[i])
            m=max(m,b[i]-a[i]);


    }
    cout <<m<<endl;
}
}