#include<cstdio>
#include<vector>
#include<queue>
using namespace std;
int n,m,k,l[20],viz[2010],d[2010];
struct punct
{
    int p,di;
};
vector<punct>v[2010];
queue<int>q;
void citire()
{
    int x,y,z;
    punct a,b;
    scanf("%d%d%d",&n,&m,&k);
    for(int i=1;i<=k;i++)
            scanf("%d",&l[i]);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d%d",&x,&y,&z);
        a.p=y;a.di=z;b.p=x;b.di=z;
        v[x].push_back(a);
        v[y].push_back(b);
    }
    for(int i=2;i<=n;i++)
            d[i]=1999999999;
}
void parcurgere()
{
    int x;
    while(!q.empty())
    {
        x=q.front();
        for(int i=0;i<v[x].size();i++)
        {
            if(d[x]+v[x][i].di<d[v[x][i].p])
            {
                d[v[x][i].p]=d[x]+v[x][i].di;
                if(viz[v[x][i].p]==0)
                {
                    q.push(v[x][i].p);
                    viz[v[x][i].p]=1;
                }
            }
        }
        q.pop();
        viz[x]=0;
    }
}
int main()
{
    freopen("ubuntzei.in","r",stdin);
    freopen("ubuntzei.out","w",stdout);

    citire();
    q.push(1);
    viz[1]=1;
    parcurgere();
    printf("%d\n",d[n]);
}