#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<to;x++)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

class UF {
	public:
	static const int ufmax=5052;
	int ufpar[ufmax],ufrank[ufmax],ufcnt[ufmax];
	UF() { int i; FOR(i,ufmax) { ufpar[i]=i; ufrank[i]=0; ufcnt[i]=1; } }
	int operator[](int x) {return (ufpar[x]==x)?(x):(ufpar[x] = operator[](ufpar[x]));}
	int count(int x) { return ufcnt[operator[](x)];}
	void unite(int x,int y) {
		x = operator[](x); y = operator[](y);
		if(x==y) return;
		if(ufrank[x]<ufrank[y]) ufpar[x]=y, ufcnt[y]+=ufcnt[x];
		else {ufpar[y]=x; ufcnt[x]+=ufcnt[y]; if(ufrank[x]==ufrank[y]) ufrank[x]++;}
	}
};

int N,M,T;
int A[2000],B[2000],C[2000];
int V[2000];
int mat[40][40];

int ok[40];

void solve() {
	int i,j,k,l,r,x,y; string s;
	UF uf;
	
	FOR(x,40) FOR(y,40) mat[x][y]=100000000;
	FOR(x,40) mat[x][x]=0;
	cin>>N>>M>>T;
	FOR(i,M) {
		cin>>A[i]>>B[i]>>C[i];
		mat[A[i]-1][B[i]-1]=mat[B[i]-1][A[i]-1]=C[i];
	}
	FOR(i,N) FOR(x,N) FOR(y,N) mat[x][y]=min(mat[x][y],mat[x][i]+mat[i][y]);
	FOR(i,T) cin>>V[i], V[i]--, ok[V[i]]=1;
	priority_queue<pair<int,int> > Q;
	FOR(x,N) FOR(y,N) if(x!=y && ok[x]&&ok[y]) Q.push(make_pair(-mat[x][y],x*100+y));
	
	int tot=0;
	while(Q.size()) {
		pair<int,int> p=Q.top();
		Q.pop();
		x=p.second/100, y=p.second%100;
		if(uf[x]!=uf[y]) {
			tot+=-p.first;
			uf.unite(x,y);
		}
	}
	cout<<tot<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false);
	FOR(i,argc-1) s+=argv[i+1],s+='\n';
	FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	solve(); return 0;
}