import heapq

N,K,M,P = map(int,input().split())
G = [ [] for _ in range(N)]
for i in range(M):
    u,v = map(int,input().split())
    u -= 1;v -= 1
    G[u].append(v)
    G[v].append(u)
S = [int(input()) for _ in range(N)]
X = [int(input())-1 for _ in range(K)]

# {イベントが起こる日,イベントの種類,起こる頂点}
que = []
heapq.heapify(que)
Ans = 0

#回復したか
recovered = [False]*N
#検疫が入ったか
quarantined = [False]*N
#いま感染しているか
infected = [False]*N

#0: 回復 1: 隣に感染 2:検疫 
for i in range(K):
    infected[X[i]] = True
    heapq.heappush(que, [P,0,X[i]])
    heapq.heappush(que, [S[X[i]],1,X[i]])

while len(que)>0:
    q = heapq.heappop(que)

    #検疫が入った場合その後一切のアクションを起こさない
    if quarantined[q[2]]:
        continue

    if q[1] == 0:
        #回復
        infected[q[2]] = False
        recovered[q[2]] = True
    elif q[1] == 1:
        #隣にうつす
        for e in G[q[2]]:
            if recovered[e] or quarantined[e]:
                continue
            #すでにかかっていた場合検疫送り
            if infected[e]:
                heapq.heappush(que, [q[0],2,e])
            else:
                infected[e] = True
                heapq.heappush(que, [q[0]+P,0,e])
                heapq.heappush(que, [q[0]+S[e],1,e])
    else:
        #検疫
        Ans += 1
        infected[q[2]] = False
        quarantined[q[2]] = True

print(Ans)