1 #include <cstdio>
 2 #include <iostream>
 3 #include <cstring>
 4 #include <algorithm>
 5 using namespace std;
 6 const int N=1e5+10,M=1e6+10;
 7 int n,m,num,tot,K,Ans,cnt[2],sum[N],head[2][N],f[N],a[N],Num[N],bel[N],ans[N],fa[N],dfn[N],low[N],p[N];
 8 bool b[N],vis[N];
 9 struct edge { int x,y; }e[2][M];
10 void insert(int p,int x,int y) { e[p][++cnt[p]].x=y,e[p][cnt[p]].y=head[p][x],head[p][x]=cnt[p]; }
11 int getfather(int x) { return fa[x]==x?x:fa[x]=getfather(fa[x]); }
12 void Tarjan(int x)
13 {
14     dfn[x]=low[x]=++dfn[0],p[++tot]=x,vis[x]=1;
15     for (int i=head[0][x];i;i=e[0][i].y)
16         if (!bel[e[0][i].x])
17         {
18             if (vis[e[0][i].x]) low[x]=min(low[x],dfn[e[0][i].x]);
19             else Tarjan(e[0][i].x),low[x]=min(low[x],low[e[0][i].x]);
20         }
21     if (dfn[x]==low[x])
22     {
23         num++; int v;
24         do
25         {
26             v=p[tot--],bel[v]=num,sum[num]+=a[v],vis[v]=0;
27         }while(v!=x);
28     }
29 }
30 void work(int x)
31 {
32     b[x]=1,f[x]+=sum[x];
33     for (int i=head[1][x];i;i=e[1][i].y)
34     {
35         getfather(x),getfather(e[1][i].x);
36         fa[fa[x]]=fa[e[1][i].x],Num[e[1][i].x]--,f[e[1][i].x]=max(f[x],f[e[1][i].x]);
37         if (!Num[e[1][i].x]) work(e[1][i].x);
38     }
39 }
40 int main()
41 {
42     freopen("azeroth.in","r",stdin),freopen("azeroth.out","w",stdout),scanf("%d%d",&n,&m);
43     for (int i=1,x,y;i<=m;i++) { scanf("%d%d",&x,&y); if (x==y) continue; insert(0,x,y); }
44     for (int i=1;i<=n;i++) scanf("%d",&a[i]);
45     scanf("%d",&K);
46     for (int i=1;i<=n;i++) if (!bel[i]) Tarjan(i);
47     for (int i=1;i<=n;i++)
48         for (int j=head[0][i];j;j=e[0][j].y)
49             if (bel[i]!=bel[e[0][j].x])
50                 insert(1,bel[i],bel[e[0][j].x]),Num[bel[e[0][j].x]]++;
51     for (int i=1;i<=num;i++) fa[i]=i;
52     for (int i=1;i<=num;i++) if (!Num[i]&!b[i]) work(i);
53     for (int i=1;i<=num;i++) getfather(i),ans[fa[i]]=max(ans[fa[i]],f[i]);
54     sort(ans+1,ans+num+1);
55     for (int i=num;i>=max(1,num-K);i--) Ans+=ans[i];
56     printf("%d",Ans);
57 }