n,m,x = map(int, input().split())
AB = []
for i in range(n):
    a, b = map(int, input().split())
    b -= 1
    AB.append((a, b))
k = int(input())
C = list(map(int, input().split()))
from itertools import accumulate
imos = [0]*(n+1)
for c in C:
    imos[0] += 1
    imos[c] -= 1
imos = list(accumulate(imos))
from collections import defaultdict
d = defaultdict(lambda: [])
for a, b in AB:
    d[b].append(a)
L = []
for k, l in d.items():
    l.sort(reverse=True)
    l[0] += x
    L += l
L.sort(reverse=True)
ans = 0
for i in range(n):
    ans += imos[i]*L[i]
print(ans)