#include <iostream>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <algorithm>

using namespace std;

struct point
{
	int x,y;
}P[100001];

int n,m,T;

bool cmp(const point &a,const point &b)
{
	return (a.x < b.x);
}

double dis(int u,int v)
{
	return sqrt((double)(P[u].x-P[v].x)*(double)(P[u].x-P[v].x)+(double)(P[u].y-P[v].y)*(double)(P[u].y-P[v].y));
}

int main()
{
	freopen("faraway.in","r",stdin);
	freopen("faraway.out","w",stdout);
	scanf("%d",&T);
	for (;T;--T)
	{
		scanf("%d%d",&m,&n);
		for (int i=1;i<=n+m;i++)
		scanf("%d%d",&P[i].x,&P[i].y);
		sort(P+1,P+n+m+1,cmp);
		double ans=0;
		for (int i=1;i<=n;i++)
		for (int j=n+1;j<=n+m;j++)
		ans=max(ans,dis(i,j));
		printf("%0.3lf\n",ans);
	}
	return 0;
}