from collections import Counter
import heapq
import sys
input = sys.stdin.buffer.readline
sys.setrecursionlimit(10 ** 7)


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

used = [False] * M
order = []
heapq.heapify(P)
Q = []


def push(que):
    a, b = heapq.heappop(que)
    used[b] = True
    order.append((-a, b))


for _ in range(N):
    while P and used[P[0][1]]:
        heapq.heappush(Q, heapq.heappop(P))
    if P and Q:
        if (-P[0][0] + X) > -Q[0][0]:
            push(P)
        else:
            push(Q)
    elif P:
        push(P)
    else:
        push(Q)

K = int(input())
C = Counter(map(int, input().split()))
ans = 0
used = [False] * M
score = 0
for i, (a, b) in enumerate(order, 1):
    score += a
    if not used[b]:
        score += X
    used[b] = True
    ans += C[i] * score

print(ans)