long long main()

#include<iostream>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<algorithm>
#include<queue>
using namespace std;
inline long long min(long long a,long long b){return a<b?a:b;}
inline long long max(long long a,long long b){return a>b?a:b;}
inline long long rd()
{long long x=0,f=1;char c=getchar();for(;!isdigit(c);c=getchar()) if(c=='-') f=-1;for(;isdigit(c);c=getchar()) x=x*10+c-'0';return x*f;
}
inline void write(long long x)
{if(x<0) putchar('-'),x=-x;if(x>9) write(x/10);putchar(x%10+'0');
}
long long n,m,k;
long long head[100006],to[1000006],v[1000006],nxt[1000006];
long long total=0;
long long dis[100006];
long long dis2[100006];
long long book[100006];
void add(long long x,long long y,long long z){total++;to[total]=y;v[total]=z;nxt[total]=head[x];head[x]=total;return ;
}
deque <long long> q;
long long vis[100006];
void spfa_r(long long x){//SPFA板子 if(book[x]) return ;memset(dis,127,sizeof(dis));memset(vis,0,sizeof(vis));q.push_back(x);vis[x]=1;dis[x]=0;while(!q.empty()){long long h=q.front();q.pop_front();vis[h]=0;for(long long e=head[h];e;e=nxt[e]){if(book[to[e]]) continue;if(dis[to[e]]>dis[h]+v[e]){dis[to[e]]=dis[h]+v[e];if(!vis[to[e]]){if(!q.empty()&&dis[to[e]]<=dis[q.front()]) q.push_front(to[e]);else q.push_back(to[e]);vis[to[e]]=1;}}}}return ;
}
void spfa_h(long long x){memset(dis2,127,sizeof(dis2));memset(vis,0,sizeof(vis));q.push_back(x);vis[x]=1;dis2[x]=0;while(!q.empty()){long long h=q.front();q.pop_front();vis[h]=0;for(long long e=head[h];e;e=nxt[e]){if(dis2[to[e]]>dis2[h]+v[e]){dis2[to[e]]=dis2[h]+v[e];if(!vis[to[e]]){if(!q.empty()&&dis2[to[e]]<=dis2[q.front()]) q.push_front(to[e]);else q.push_back(to[e]);vis[to[e]]=1;}}}}return ;
}
int main()
{n=rd(),m=rd(),k=rd();for(long long i=1;i<=k;i++){long long x=rd();book[x]=1;}for(long long i=1;i<=m;i++){long long x=rd(),y=rd(),z=rd();add(x,y,z);add(y,x,z);}long long l=rd(),r=rd();spfa_r(1);//因为有的房间只有Harry能去 spfa_h(1);//所以要分开写（滑稽） long long ans=min(max(dis2[l],dis[r]),max(dis2[r],dis[l]));//两个人去的房间取最优（在这里卡了半天） long long set=dis2[l];long long sett=dis2[r];spfa_h(l);//Harry先从l点开始 ans=min(ans,set+dis2[r]);spfa_h(r);//刚才把这行写在了上面 ans=min(ans,sett+dis2[l]);printf("%lld",ans);return 0;
}