n,m,x=map(int,input().split())
genre=[[] for i in range(m+1)]
for _ in range(n):
  a,b=map(int,input().split())
  genre[b].append(a)

c=[]
for i in range(m+1):
  if genre[i]:
    genre[i].sort(reverse=True)
    c.append(genre[i][0]+x)
    for j in genre[i][1:]:
      c.append(j)

c.sort(reverse=True)
cum=[0]*(n+1)
for i in range(n):
  cum[i+1]=cum[i]+c[i]

ans=0
k=input()
for i in list(map(int,input().split())):
  ans+=cum[i]

print(ans)