#include <bits/stdc++.h>

 using namespace std;

 typedef pair<int,int> pii;

 const int maxn = ;

 struct arc{

     int to,cost,next;

     arc(int x = ,int y = ,int z = -){

         to = x;

         cost = y;

         next = z;

     }

 }e[];

 int head[maxn],cnt[maxn],d[maxn],tot,N,M,K;

 void add(int u,int v,int w){

     e[tot] = arc(v,w,head[u]);

     head[u] = tot++;

 }

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

 bool done[maxn];

 void dijkstra(){

     while(!q.empty()) q.pop();

     memset(d,0x3f,sizeof d);

     memset(cnt,,sizeof cnt);

     q.push(pii(d[] = ,cnt[] = ));

     while(!q.empty()){

         int u = q.top().second;

         q.pop();

         if(done[u]) continue;

         done[u] = true;

         for(int i = head[u]; ~i; i = e[i].next){

             if(d[e[i].to] > d[u] + e[i].cost){

                 d[e[i].to] = d[u] + e[i].cost;

                 cnt[e[i].to] = cnt[u];

                 q.push(pii(d[e[i].to],e[i].to));

             }else if(d[e[i].to] == d[u] + e[i].cost)

                 cnt[e[i].to]++;

         }

     }

 }

 int main(){

     int x,u,v,w;

     while(~scanf("%d%d%d",&N,&M,&K)){

         memset(head,-,sizeof head);

         while(K--) scanf("%d",&x);

         for(int i = tot = ; i < M; ++i){

             scanf("%d%d%d",&u,&v,&w);

             add(u,v,w);

             add(v,u,w);

         }

         dijkstra();

         puts(cnt[N] > ?"yes":"no");

     }

     return ;

 }

 /*

 3 3 3

 1 2 3

 1 2 1

 2 3 2

 1 3 3

 4 5 2

 1 4

 1 2 2

 2 4 1

 1 3 1

 3 4 2

 1 4 2

 */