#include<bits/stdc++.h>

 #define LL long long

 #define fi first

 #define se second

 #define mk make_pair

 #define pii pair<int,int>

 using namespace std;

 const int N=5e5+;

 const int M=1e4+;

 const int inf=0x3f3f3f3f;

 const LL INF=0x3f3f3f3f3f3f3f3f;

 const int mod=1e9 + ;

 struct edge {

     int from, to, nx;

 }e[N];

 bool bar[N], flag[N], in[N], ok[N];

 int n, m, tot, cnt, S, p, idx, top, head[N], a[N], sum[N], dfn[N], low[N], id[N], f[N], st[N];

 vector<int> edge[N];

 void add(int from, int to) {

     e[tot].from = from;

     e[tot].to = to;

     e[tot].nx = head[from];

     head[from] = tot++;

 }

 void tarjan(int u) {

     ++idx;

     dfn[u] = low[u] = idx;

     st[top++] = u; in[u] = true;

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

         int v = e[i].to;

         if(!dfn[v]) {

             tarjan(v);

             low[u] = min(low[u], low[v]);

         } else if(in[v]) {

             low[u] = min(low[u], dfn[v]);

         }

     }

     if(low[u] == dfn[u]) {

         cnt++;

         while() {

             int now = st[--top];

             in[now] = false;

             id[now] = cnt;

             if(now == u) break;

         }

     }

 }

 int dp(int u) {

     if(f[u] != -) return f[u];

     f[u] = ;

     for(int i = ; i < edge[u].size(); i++) {

         int v = edge[u][i];

         int ret = dp(v);

         if(ok[v]) {

             ok[u] = true;

             f[u] = max(f[u], f[v]);

         }

     }

     if(!ok[u]) return f[u];

     return f[u] = f[u] + sum[u];

 }

 int main() {

     memset(head, -, sizeof(head));

     memset(f, -, sizeof(f));

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

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

         int from, to; scanf("%d%d", &from, &to);

         add(from, to);

     }

     for(int i = ; i <= n; i++)

         scanf("%d", &a[i]);

     scanf("%d%d", &S, &p);

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

         int x; scanf("%d", &x);

         flag[x] = true;

     }

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

         if(!dfn[i]) tarjan(i);

     }

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

         sum[id[i]] += a[i];

         bar[id[i]] |= flag[i];

     }

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

         int u = e[i].from, v = e[i].to;

         if(id[u] != id[v]) {

             edge[id[v]].push_back(id[u]);

         }

     }

     S = id[S];

     ok[S] = true;

     int ans = ;

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

         if(bar[i]) {

             ans = max(ans, dp(i));

         }

     }

     printf("%d\n", ans);

     return ;

 }

 /*

 */