import heapq 
import itertools
import collections

d = collections.defaultdict(list)

N,M,X = map(int, input().split())
for i in range(N):
    a,b = map(int, input().split())
    heapq.heappush(d[b],-a)

MQ = [(1,0)]
for k,v in d.items():
    q = heapq.heappop(v)
    heapq.heappush(MQ, (q,k))  


USED = [0]
K = int(input())
C = list(map(int, input().split()))
CNT = [0]*(N+2)
CNT[0] = K
for c in C:
    CNT[c+1]-=1
AC = list(itertools.accumulate(CNT))
ans = 0
for i in range(1,N+1):
    mused = heapq.heappop(USED)
    mqq,mqk = heapq.heappop(MQ)

    if mqk != 0 and mused>=mqq-X:
        ans -= (mqq-X)*AC[i]
        heapq.heappush(USED, mused)
        while len(d[mqk]):
            temp = heapq.heappop(d[mqk])
            heapq.heappush(USED, temp)
    else:
        ans -= mused*AC[i]
        heapq.heappush(MQ, (mqq,mqk))
print(ans)