/*mahendra25---PVPSIT-IT
IT ONLY HAS TO WORK ONCE!
*/
#include<bits/stdc++.h>
using namespace std;
#define pi 3.14159265358979323846264338327950
const int N=1e6+20,mod=(int)(1e9)+7;
#define pb push_back
#define ull unsigned long long
#define ll long long 
 int main(){
  // freopen("input.txt", "r", stdin);
  // freopen("output.txt", "w", stdout);
   int T;
   scanf("%d",&T);
   while(T--){
  		int a,b;
  		cin>>a;
  		int arr[a];
  		for(int i=0;i<a;i++)
  			cin>>arr[i];
  		cin>>b;
  		int arr1[b],diff=1e5;
  		for(int i=0;i<b;i++)
  			cin>>arr1[i];
   		for(int i=0;i<a;i++)
   			for(int j=0;j<b;j++)
   				if(abs(arr[i]-arr1[j])<diff)
   					diff=abs(arr[i]-arr1[j]);
   		cout<<diff<<endl;
   }
  return(0);
} 

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Mgo4IDEgMyA1IDcgOSA3IDMgMQo4IDIgNCA2IDggMTAgOCA2IDIKOCAyIDMgNSAxMCA5IDMgMiAxCjcgMSAyIDYgMTIgMTMgMyAy

2
8 1 3 5 7 9 7 3 1
8 2 4 6 8 10 8 6 2
8 2 3 5 10 9 3 2 1
7 1 2 6 12 13 3 2