#include<bits/stdc++.h>
using namespace std;#define N 500000
#define M 500000
#define INF 0x3f3f3f3fint dfn[N],low[N],vis[N],first[N],color[N],siz[N];
int w[N],jg[N],atm[N];
int head[N],visit[N],dis[N];
int cnt=0,cot=0,tot=0,num=0,n,m,ss,p,ans=0;
stack <int> s;
queue <int> q;struct email
{int u,v,w;int nxt;
}e[M*2],edge[M*2];inline void read(int &x)
{x=0;int f=1;char c=getchar();while(c<'0'||c>'9'){if(c==-1)f=-1;c=getchar();}while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}x*=f;
}inline void add(int u,int v)
{e[++cnt].nxt=first[u];first[u]=cnt;e[cnt].u=u;e[cnt].v=v;
}inline void readd(int u,int v,int w)
{edge[++cot].nxt=head[u];head[u]=cot;edge[cot].u=u;edge[cot].v=v;edge[cot].w=w;
}void tarjan(int u)
{dfn[u]=low[u]=++tot;vis[u]=1;s.push(u);for(int i=first[u];i;i=e[i].nxt){int v=e[i].v;if(!dfn[v]){tarjan(v);low[u]=min(low[u],low[v]);}elseif(vis[v])low[u]=min(low[u],dfn[v]);    }if(dfn[u]==low[u]){num++;while(1){int t=s.top();s.pop();vis[t]=0; siz[num]++;color[t]=num;atm[num]+=w[t];if(t==u)break;}}
}void spfa(int start)
{for(int i=1;i<=n;i++)dis[i]=INF;dis[start]=-atm[start];q.push(start);visit[start]=1;while(!q.empty()){int u=q.front();q.pop();visit[u]=0;for(int i=head[u];i;i=edge[i].nxt){int v=edge[i].v;int w=edge[i].w;if(dis[v]>dis[u]+w)dis[v]=dis[u]+w;if(!visit[v]){visit[v]=1;q.push(v);}}}
}void readin()
{read(n);read(m);for(int i=1;i<=m;i++){int u,v;read(u);read(v);add(u,v);}for(int i=1;i<=n;i++)read(w[i]);read(ss);read(p);for(int i=1;i<=p;i++)read(jg[i]);
}int main()
{readin();for(int i=1;i<=n;i++)if(!dfn[i])tarjan(i);for(int i=1;i<=n;i++)for(int k=first[i];k;k=e[k].nxt){int j=e[k].v;if(color[i]==color[j])continue;readd(color[i],color[j],-atm[color[j]]);    }spfa(color[ss]);for(int i=1;i<=p;i++)ans=max(ans,-dis[color[jg[i]]]);printf("%d",ans);
}