#include <iostream>
#include <cstdio>
#include <memory.h>
#include <queue>
#include <algorithm>
using namespace std;
const int N=1e5+10;
struct Edge {
    int u,v,nx;
}g[10*N];
int cnt,list[N],val[N],w[N],f[N],deg[N],fa[N],ans[N];
int low[N],dfn[N],tme;
int stk[N],top,bel[N],id,stack[N],tp,icnt;
bool instk[N],vis[N];
int n,m,k;

int Get_F(int x) {return fa[x]==x?x:fa[x]=Get_F(fa[x]);}

void Add(int u,int v) {g[++cnt]=(Edge){u,v,list[u]};list[u]=cnt;}

void Tarjan(int v0) {
    stack[++tp]=v0;
    while (tp) {
        int u=stack[tp],i;
        if (!dfn[u]) low[u]=dfn[u]=++tme,stk[++top]=u,instk[u]=1;
        for (i=list[u];i;i=g[i].nx)
            if (!dfn[g[i].v]) break;
            else if (instk[g[i].v]) low[u]=min(low[u],dfn[g[i].v]);
        if (!i&&tp>1) low[stack[tp-1]]=min(low[stack[tp-1]],low[u]);
        if (!i) {
            if (dfn[u]==low[u]) {
                ++id;
                do {
                    bel[stk[top]]=id;instk[stk[top]]=0;w[id]+=val[stk[top]];
                }
                while (stk[top--]!=u);
            }
            tp--;
        }
        else stack[++tp]=g[i].v;
    }
}

bool CMP(int a,int b) {
    return a>b;
}

void ToppoSort() {
    queue<int> q;
    while (!q.empty()) q.pop();
    for (int i=1;i<=id;i++) if (!deg[i]) q.push(i);
    while (!q.empty()) {
        int u=q.front();q.pop();f[u]+=w[u];
        for (int i=list[u];i;i=g[i].nx) {
            f[g[i].v]=max(f[g[i].v],f[u]);deg[g[i].v]--;
            if (!deg[g[i].v]) q.push(g[i].v);
        }
    }
    for (int i=1;i<=id;i++)
        ans[Get_F(i)]=max(ans[Get_F(i)],f[i]),icnt+=!vis[Get_F(i)],vis[Get_F(i)]=1;
    sort(ans+1,ans+n+1,CMP);
    int lans=0;
    for (int i=1;i<=min(k+1,icnt);i++) lans+=ans[i];
    printf("%d\n",lans);
}

int main() {
    freopen("azeroth.in","r",stdin);freopen("azeroth.out","w",stdout);
    scanf("%d%d",&n,&m);
    for (int i=1,u,v;i<=m;i++) scanf("%d%d",&u,&v),Add(u,v);
    for (int i=1;i<=n;i++) scanf("%d",&val[i]);
    scanf("%d",&k);
    for (int i=1;i<=n;i++) if (!dfn[i]) Tarjan(i);
    cnt=0;memset(list,0,sizeof list);
    for (int i=1;i<=id;i++) fa[i]=i;
    for (int i=1;i<=m;i++)
        if (bel[g[i].u]!=bel[g[i].v])
            deg[bel[g[i].v]]++,fa[Get_F(bel[g[i].u])]=Get_F(bel[g[i].v]),Add(bel[g[i].u],bel[g[i].v]);
    ToppoSort();
}