#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <vector>
 
using namespace std;
 
int i,j,n,m,k;
 
int C[512][512];
 
int _min[64][64][64];
 
int P[64][64];
 
int D[64];
 
int v,e;
 
void readdata(){
     memset(C,1,sizeof(C));
     FILE *f=fopen ("team.in","r");
     fscanf (f,"%d",&n);
     fscanf (f,"%d%d",&v,&e);
      
     for (i=1;i<=e;i++)
     {
        int a,b,c;
        fscanf (f,"%d%d%d",&a,&b,&c);
 
        C[a][b]=C[b][a]=c;
     }
     D[0]=1;
     for (i=1;i<=n;i++)
         fscanf (f,"%d",&D[i]);
}
 
int X[512];
int s[512];
 
void djikstra(int x){
     memset(X,127,sizeof(X));
     X[x]=0;
     memset(s,0,sizeof(s));
 
     int i,j;
      
     for (i=1;i<=v;i++){
         int _min=0;
         for (j=1;j<=v;j++)
             if (!s[j]&&X[j]<X[_min]) _min=j;
 
         for (j=1;j<=v;j++)
             if (X[_min]+C[_min][j]<X[j])
                X[j]=X[_min]+C[_min][j];
         s[_min]=1;
     }     
}
 
void reduce_graph(){
     for (i=0;i<=n;i++)
     {
        djikstra(D[i]);
        for (j=0;j<=n;j++)
                P[i][j]=X[D[j]];
     }
}
 
#define MIN(a,b) ((a)<(b)?(a):(b))
 
int get(int j,int x,int y){
     if (x>y) return 0;
     if (_min[j][x][y]>=0) return _min[j][x][y];
     if (x==y&&j==x) return 0;
 
     _min[j][x][y]=1000000000;
      
     for (int k=x;k<=y;k++)
         _min[j][x][y]=MIN(_min[j][x][y],P[j][k]+get(k,x,k-1)+get(k,k+1,y));
          
     return _min[j][x][y];
}
 
int main(){
    readdata();
    reduce_graph();
    memset(_min,255,sizeof(_min));
    fprintf (fopen ("team.out","w"),"%d\n",get(0,1,n));
 
    return 0;
}