#include <iostream>
#include <fstream>
#define inf 2000000000
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");
int n,m,k,i,j,p,v[2001],a[2001][2001],cost,x,y,c;
int main()
{
    fin>>n>>m;
    fin>>p;
    for(i=1;i<=p;i++)
        fin>>v[i];
    v[0]=1;
    for(i=1;i<=n;i++)
        for(j=1;j<=n;j++)
          if(i!=j) a[i][j]=inf;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>c;
        a[x][y]=a[y][x]=c;
    }
    for(k=1;k<=n;k++)
        for(i=1;i<=n;i++)
            for(j=1;j<=n;j++)
              if(a[i][j]>a[i][k]+a[k][j]&&i!=k&&k!=j)
                a[i][j]=a[i][k]+a[k][j];

    for(i=1;i<=p;i++)
       cost+=a[v[i-1]][v[i]];
    fout<<cost+a[v[p]][n];
    return 0;
}