#include <stdio.h>
using namespace std;
int m,n,C[2002][2002],x[2002],nod1,nod2,cost,viz[2002], d[2002], tata[2002];;
void dijkstra(int x0)
{
    int i, j, minim, k, ok;
    for (i = 1; i<=n; i++)
    {
        d[i] = C[x0][i];
        tata[i] = x0;
        viz[i] = 0;
    }
    tata[x0] = 0;
    viz[x0] = 1; ok = 1;
    while (ok) {
        minim = 3500;
        for (i = 1; i<=n; i++)
            if (!viz[i] && minim>d[i]) {
                minim = d[i];
                k = i;
            }
        if (minim != 3500) {
            viz[k] = 1;
            for (i = 1; i<=n; i++)
               if (!viz[i] && d[i]>d[k]+C[k][i]) {
                   d[i] = d[k]+C[k][i];
                   tata[i] = k;
               }
        }
        else ok = 0;
    }
    printf("%d",d[n]);
}

int main()
{
    freopen("ubuntzei.in","r",stdin);
    freopen("ubuntzei.out","w",stdout);
    scanf("%d %d %d",&n,&m,&x[0]);
    for(int i=1;i<=n;++i)
    {
        for(int j=1;j<=n;++j)
        {
            C[i][j]=3500;
        }
        C[i][i]=0;
    }
    for(int i=1;i<=x[0];++i)
    {
        scanf("%d",&x[i]);
    }
    for(int i=1;i<=m;++i)
    {
        scanf("%d %d %d",&nod1,&nod2,&cost);
        C[nod1][nod2]=cost;
        C[nod2][nod1]=cost;
    }
    /*for(int i=1;i<=n;++i)
    {
        for(int j=1;j<=n;++j)
        {
            printf("%d ",C[i][j]);
        }
        printf("\n");
    }
    printf("\n");*/
    dijkstra(1);
    return 0;
}