#include<bits/stdc++.h>

 #define pa pair<int,int>

 #define lld long long

 using namespace std;

 #define N 30007

 #define M 100007

 #define inf 100000000000000LL

 namespace Dinic

 {

     int head[N],head2[N],p=;

     struct Rec

     {

         int go,nex;

         lld c;

     }eg[M*],e[M*];

     void build(int a,int b,lld c)

     {

         //printf("%d %d %d\n",a,b,c);

         eg[++p]=(Rec){b,head[a],-c};

         head[a]=p;

         eg[++p]=(Rec){a,head[b],};

         head[b]=p;

     }

     lld dis[N],ans;

     int Q[N],s[N],S,T,stop;

     bool bfs()

     {

         memset(dis,,sizeof(dis));

         dis[T]=;

         Q[]=T;

         for (int p1=,p2=;p1<=p2;p1++)

         {

             for (int i=head[Q[p1]];i;i=eg[i].nex)

                 if (eg[i^].c<&&!dis[eg[i].go])

                 {

                     dis[eg[i].go]=dis[Q[p1]]+;

                     Q[++p2]=eg[i].go;

                 }

         }

         if (!dis[S]) return false;

         memcpy(head2,head,sizeof(head));

         return true;

     }

     bool dinic(int p,int top)

     {

         if (p==T)

         {

             lld x=inf;

             for (int i=;i<=top-;i++) if (-eg[s[i]].c<x) x=-eg[s[i]].c,stop=i;

             for (int i=;i<=top-;i++) eg[s[i]].c+=x,eg[s[i]^].c-=x;

             ans+=x;

             return true;

         }

         for (int &i=head2[p];i;i=eg[i].nex)

         {

             if (eg[i].c<&&dis[eg[i].go]==dis[p]-)

             {

                 s[top]=i;

                 if (dinic(eg[i].go,top+)&&top!=stop) return true;

             }

         }

         return false;

     }

     lld ask()

     {

         ans=;

         while (bfs()) dinic(S,);

         return ans;

     }

     void init(int _S,int _T){

         S=_S,T=_T;

     }

 }

 using namespace Dinic;

 void clear()

 {

     p=;

     memset(head,,sizeof(head));

 }

 int n,m,ss,tt,why=;

 long long diss[N];

 void addedge(int a,int b,lld c)

 {

     p++;

     e[p].go=b;

     e[p].c=c;

     e[p].nex=head[a];

     head[a]=p;

 }

 void dijkstra()

 {

     priority_queue<pa,vector<pa>,greater<pa> >q;

     for (int i=;i<=n;i++) diss[i]=inf;

     diss[]=;

     q.push(make_pair(,));

     while (!q.empty())

     {

         int now=q.top().second;

         q.pop();

         for (int i=head[now];i;i=e[i].nex)

             if(diss[now]+e[i].c<diss[e[i].go])

             {

                 diss[e[i].go]=diss[now]+e[i].c;

                 q.push(make_pair(diss[e[i].go],e[i].go));

             }

     }

 }

 int u[M],v[M],w[M],pos[M],c;

 void solve(int l, int r)

 {

     clear();

     ss=n+;

     tt=n+;

     init(ss,tt);

     for(int i = ; i <= m; i++) build(u[i], v[i], );

     for(int i = l; i <= r; i++) build(pos[i], tt, );

     build(ss, , r - l + );

     why += ask();

     //cout << ans <<endl;

 }

 bool cmp_(int a, int b) {

     return diss[a] < diss[b];

 }

 int main()

 {

     scanf("%d%d%d", &n, &m, &c);

     p=;

     for(int i = ; i <= m; i++) scanf("%d%d%d", &u[i], &v[i], &w[i]);

     for(int i = ; i <= c; i++) scanf("%d", &pos[i]);

     for(int i = ; i <= m; i++) addedge(u[i], v[i], w[i]), addedge(v[i], u[i], w[i]);

     dijkstra();

     //for (int i=1;i<=n;i++) printf("%d\n",diss[i]);

     int tmp = ;

     for(int i = ; i <= m; i++) {

         if(diss[u[i]] > diss[v[i]]) swap(u[i], v[i]);

         if(diss[v[i]] == diss[u[i]] + w[i]) {

             ++tmp;

             swap(u[i], u[tmp]);

             swap(v[i], v[tmp]);

             swap(w[i], w[tmp]);

         }

     }

     m = tmp;

     sort(pos + , pos + c + , cmp_);

     for(int i = , j; i <= c; i = j) {

         j = i;

         while(diss[pos[i]] == diss[pos[j]] && j <= c) j++;

         if (diss[pos[i]]==inf) break;

         solve(i, j - );

         //cout << i << " " << j  - 1 <<endl;

     }

     printf("%d", why);

     return ;

 }