/*
 Author                             :     unlucky_13
 Problem_link                       :
 Category                           :
 Algorithm_Used                     :
 */

#include<cstdio>
#include<sstream>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<algorithm>
#include<set>
#include<queue>
#include<stack>
#include<list>
#include<iostream>
#include<fstream>
#include<numeric>
#include<string>
#include<vector>
#include<cstring>
#include<map>
#include<iterator>
#define LL long long int
const long long int inf = 2147483647 ;
//const int minx=;
//const int maxn=;

using namespace std;
int inter,f,dis[555][555],d[555],fire[555];
struct data{
    int u,cost ;
    bool operator<(const data &p) const {
        return cost>p.cost ;
    }
};
vector<int>g[555] ;

int Dijkstra(int s)
{

    for(int i=1;i<=inter;i++) d[i]=inf ;
    priority_queue<data>pq;
    data u,v ;
    u.u = s ;
    u.cost = 0 ;
    d[s] = 0 ;
    pq.push(u) ;
    for(int i=1;i<=inter;i++){
        if(fire[i]==1) {
            d[i] = 0 ;
            u.u = i ;
            u.cost = 0 ;
            pq.push(u) ;
        }
     }



    while(!pq.empty()) {
        data u = pq.top() ;
        pq.pop() ;
        for(int i=0;i<g[u.u].size();i++){


               if(d[g[u.u][i]]>u.cost+dis[u.u][g[u.u][i]]){
                v.u = g[u.u][i] ;
                v.cost = u.cost+dis[u.u][g[u.u][i]] ;
                d[g[u.u][i]] = v.cost ;
                pq.push(v) ;
            }
        }
    }

    int ret = 0 ;

    for(int i=1;i<=inter;i++)
    {
         ret = max(ret,d[i]) ; //finding the maximum distance form the fire station

    }

    //cout<<s<<" returned "<<ret<<endl ;
    return ret ;

}


int main() {

    freopen("C:\\Users\\Mazhar\\Desktop\\Text_Files\\in.txt", "r", stdin);

    int tc ,x,y,cost;
    char  line[1000] ;
    scanf("%d\n",&tc) ;

    while(tc--)
    {

        scanf("%d %d\n",&f,&inter) ;
        memset(fire,0,sizeof(fire)) ;
        memset(dis,0,sizeof(dis)) ;
        for(int i=1;i<=inter;i++) g[i].clear() ;

        for(int i=0;i<f;i++){
            scanf("%d",&x) ;
            fire[x] = 1 ;
        }

        gets(line) ;
        while(gets(line))
        {

            if(line[0]=='\0') break ;
            sscanf(line,"%d %d %d",&x,&y,&cost) ;
            //cout<<x<<" "<<y<<" "<<cost<<endl ;
            g[x].push_back(y) ;
            g[y].push_back(x) ;
            dis[x][y] = cost ;
            dis[y][x] = cost ;

        }
        //cout<<"-------------------"<<endl ;
        int MIN = inf ,res=-1 ;
        for(int i=1;i<=inter;i++){
            int DIS = Dijkstra(i) ;
            if(MIN>DIS) {
                res = i ;
                MIN = DIS ;
            }
        }
        if(res==-1){
             res = 1 ;
            while(fire[res]==1) res++ ;
        }
        cout<<res<<endl ;
        if(tc) cout<<endl ;


    }



    return 0;

}