N,M,X=map(int, input().split())

A=[]
B=[]
for i in range(N):
   a,b=map(int, input().split())
   A.append(a)
   B.append(b)
K=int(input())
C=list(map(int, input().split()))
AB=list(zip(A,B))
AB=sorted(AB,key=lambda x:-x[0])

used=set()
ANS=[]
for i in range(N):
    if AB[i][1] not in used:
        ANS.append(AB[i][0]+X)
        used.add(AB[i][1])
    else:
        ANS.append(AB[i][0])
        
ANS=sorted(ANS,key=lambda x:-x)

ANS2=[0]
now=0
for i in range(N):
    now+=ANS[i]
    ANS2.append(now)

ans=0
for k in range(K):
    ans+=ANS2[C[k]]
print(ans)