#include <iostream>
#include <algorithm>
#include <cmath>
#include <array>
#define scanf scanf_s
using namespace std;

int main()
{
	int t;
	int *walls;
	int *children;
	cin >> t;
	while (t--)
	{
		int n,mxm=0;
		cin>>n;
		walls = new int[n];
		children = new int[n];
		for (int i = 0; i < n; i++)
		{
			cin >> walls[i];
		}
		for (int i = 0; i < n; i++)
		{
			cin>>children[i];
			if (children[i] > walls[i]) mxm = max(mxm, children[i] - walls[i]);
		}
		printf("%d\n", mxm);
	}
}