#include<cstdio>

 #include<cmath>

 #include<cstring>

 const int qq=+;

 const int MAX=1e7;

 int s[qq],e[qq];

 int dist[qq];

 int vis[qq],tar[qq];

 int city[qq][qq];

 int t,a,b;

 void Dijkstra()

 {

     int poor=MAX;

     for(int l=;l<=a;++l){

         int tot=MAX;

         for(int i=;i<qq;++i){

             vis[i]=;

             dist[i]=city[s[l]][i];

         }

         vis[s[l]]=;

         for(int i=;i<qq;++i){

             int minx=MAX;

             int u=s[l];

             for(int j=;j<qq;++j)

                 if(!vis[j] && dist[j] < minx)

                     minx=dist[u=j];

             if(minx==MAX)    break;

             vis[u]=;

             if(tar[u]!=){

                 tot=dist[u];

                 break;

             }

             for(int j=;j<qq;++j)

                 if(!vis[j] && city[u][j] < MAX)

                     if(dist[u]+city[u][j]<dist[j])

                         dist[j] = dist[u] + city[u][j];

         }

         if(tot<poor)

             poor=tot;

     }

     printf("%d\n",poor);

 }

 int main()

 {

     while(scanf("%d %d %d",&t,&a,&b)!=EOF){

         for(int j,i=;i<qq;++i)

             for(j=;j<qq;++j)

                 city[i][j]=MAX;

         for(int i=;i<=t;++i){

             int x,y,cost;

             scanf("%d %d %d",&x,&y,&cost);

             if(cost<city[x][y])

                 city[x][y]=city[y][x]=cost;

         }

         for(int i=;i<=a;++i)

             scanf("%d",&s[i]);

         memset(tar,,sizeof(tar));

         for(int i=;i<=b;++i){

             int ans;scanf("%d",&ans);

             tar[ans]=;

         }

         Dijkstra();

     }

 }