N,M,X = map(int,input().split())
C = {i:[] for i in range(1,M+1)}
for _ in range(N):
    a,b = map(int,input().split())
    C[b].append(a)
for b in C:
    C[b] = sorted(C[b])
    if len(C[b])>0:
        C[b][-1] = C[b][-1]+X
A = []
for b in C:
    A += C[b]
A = [0]+sorted(A,reverse=True)
B = [0]*(N+1)
for i in range(1,N+1):
    B[i] = B[i-1]+A[i]
K = int(input())
D = list(map(int,input().split()))
ans = 0
for i in range(K):
    ans += B[D[i]]
print(ans)