n, m, x = map(int, input().split())
AB = [list(map(int, input().split())) for _ in range(n)]
k = int(input())
C = list(map(int, input().split()))

AB.sort(key=lambda x: x[0], reverse=True)
seen = set()
P = []
for i in range(n):
    a, b = AB[i]
    if b not in seen:
        seen.add(b)
        P.append(a + x)
    else:
        P.append(a)
P.sort(reverse=True)
accumP = [0 for _ in range(n + 1)]
for i in range(n):
    accumP[i + 1] = accumP[i] + P[i]
ans = 0
for i in range(k):
    ans += accumP[C[i]]
print(ans)