import sys
input=sys.stdin.readline

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

Q=[[] for _ in range(M+1)]
for _ in range(N):
    a,b=map(int,input().split())
    Q[b].append(a)

R=[]
for q in Q:
    q.sort(reverse=True)

    if q:
        q[0]+=X
    R+=q
R.sort(reverse=True)

K=int(input())
C=list(map(int,input().split()))

D=[0]*(N+1)
for c in C:
    D[c]+=1

for i in range(N-1,-1,-1):
    D[i]+=D[i+1]

Ans=0
for i in range(N):
    Ans+=D[i+1]*R[i]

print(Ans)