require 'set'

N, M, X = gets.split.map(&:to_i)
AB = N.times.map { gets.split.map(&:to_i) }
K = gets.to_i
C = gets.split.map(&:to_i)

ab = AB.sort_by{|ab| -ab[0]}

used = Set.new
ans = []
ab.each do |n|
  if used.add?(n[1])
    ans << n[0] + X
  else
    ans << n[0]
  end
end

ans.sort_by!{|x| -x}

ans2 = [0]
now = 0
ans.each do |x|
  now += x
  ans2 << now
end

p K.times.sum{|k| ans2[C[k]]}