1 #include<stdio.h>
 2 #define INF 0xffff
 3 #define MIN(x,y) x<y?x:y
 4 #define MAX(x,y) x>y?x:y
 5 typedef struct{
 6     int begin,end,time;
 7 }node;
 8 int city[1001][1001],start[10010],final[10010];
 9 node deta[10010];
10 int main(){//printf("%d\n",INF);
11     int T,S,D,min,max,t;
12     while(~scanf("%d%d%d",&T,&S,&D)){
13         for(int i=1;i<=1000;++i){
14             for(int j=1;j<=1000;++j){
15                  city[i][j]=city[j][i]=INF;
16             }
17         }
18         for(int i=0;i<T;++i){
19             scanf("%d%d%d",&deta[i].begin,&deta[i].end,&deta[i].time);
20             city[deta[i].end][deta[i].begin]=city[deta[i].begin][deta[i].end]=deta[i].time;
21             if(!i)min=MIN(deta[i].begin,deta[i].end),max=MAX(deta[i].begin,deta[i].end);
22             else min=MIN(min,deta[i].begin),min=MIN(min,deta[i].end),max=MAX(max,deta[i].begin),max=MAX(max,deta[i].end);
23         }
24         for(int i=0;i<S;++i){
25             scanf("%d",&start[i]);
26         }
27         for(int i=0;i<D;++i)scanf("%d",&final[i]);
28         for(int i=min;i<=max;++i){
29             for(int j=min;j<=max;++j){
30                 for(int k=min;k<=max;++k){
31                     city[j][k]=city[j][i]+city[i][k]<city[j][k]?city[j][i]+city[i][k]:city[j][k];
32                 }
33             }
34         }
35         for(int i=0;i<S;++i){
36             for(int j=0;j<D;++j){
37             if(!i&&!j)t=city[start[i]][final[j]];
38             t=MIN(t,city[start[i]][final[j]]);    
39             }
40         }
41         printf("%d\n",t);
42     }
43     return 0;
44 }