> #include<iostream>
> #include<cstdio>
> #include<string> 
> #include<algorithm>
> #include<math.h>
> using namespace std;
> struct point{
> 	int flag;
> 	int x,y;
> };
> point s[200002];
> int y[200002];
> int t,n;
> double max=9999999;
> double dis(point p1,point p2){
> 	if(p1.flag==p2.flag)
> 		return 99999999;
> 	return sqrt((p1.x-p2.x)*(p1.x-p2.x)+(p1.y-p2.y)*(p1.y-p2.y));
> }
> bool cmpx(point p1,point p2){
> 	if(p1.x==p2.x) return p1.y<p2.y;
> 	return p1.x<p2.x;
> }
> bool cmpy(point p1,point p2){
> 	if(p1.y==p2.y) return p1.x<p2.x;
> 	return p1.y<p2.y;
> }
> int x_cmp(const void *a,const void *b){
> 	if(((point*)a)->x<((point*)b)->x)
> 		return -1;
> 	else return 1;
> }
> int y_cmp(const void*a,const void*b){
> 	if(s[(*(int*)a)].y<s[(*(int*)b)].y)
> 		return -1;
> 	else
> 		return 1;
> }
> double Nearest(int first,int last){
> 	if(last-first==1)
> 		return dis(s[first],s[last]);
> 	else if(last-first==2){
> 		double d1,d2,d3,d4;
> 		d1=dis(s[first],s[first+1]);
> 		d2=dis(s[first],s[first+2]);
> 		d3=dis(s[first+1],s[first+2]);
> 		d4=(d1<d2?d1:d2);
> 		return (d3<d4?d3:d4);
> 	}
> 	int mid=(first+last)/2;
> 	double min=(Nearest(first,mid)<Nearest(mid+1,last)?Nearest(first,mid):Nearest(mid+1,last));
> 	if(min==0)
> 		return 0;
> 	int y_end=0;
> 	int i,j;
> 	double d;
> 	for(i=mid;s[mid].x-s[i].x<min&&i>=first;i--)
> 		y[y_end++]=i;
> 	for(i=mid+1;s[i].x-s[mid].x<min&&i<=last;i++)
> 		y[y_end++]=i;
> 	qsort(y,y_end,sizeof(y[0]),y_cmp);
> 	for(i=0;i<y_end;i++){
> 		for(j=i+1;j<y_end&&s[y[j]].y-s[y[i]].y<min;j++){
> 			d=dis(s[y[i]],s[y[j]]);
> 			if(min>d)
> 				min=d;
> 		}
> 		//	min=(min<dis(s[y[j]],s[y[i]])?min:dis(s[y[j]],s[y[i]]));
> 	}
> 	return min;
> }
> int main(){
> 	int i,j;
> 	scanf("%d",&t);
> 	while(t--){
> 		scanf("%d",&n);
> 		for(i=0;i<n;i++){
> 			scanf("%d%d",&s[i].x,&s[i].y);
> 			s[i].flag=0;
> 		}
> 		for(i=n;i<2*n;i++){
> 			scanf("%d%d",&s[i].x,&s[i].y);
> 			s[i].flag=1;
> 		}
> 		qsort(s,2*n,sizeof(s[0]),x_cmp);
> 		printf("%.3f\n",Nearest(0,2*n-1));
> 	}
> 	return 0;
> }