local bls, brs = bit.lshift, bit.rshift
local Heapq = {}
Heapq.create = function(self, lt)
  self.lt = lt
  self.cnt = 0
  self.t = {}
end

Heapq.push = function(self, v)
  local hqlt = self.lt
  local hqt = self.t
  local c = self.cnt + 1
  self.cnt = c
  hqt[c] = v
  while 1 < c do
    local p = brs(c, 1)
    if hqlt(hqt[c], hqt[p]) then
      hqt[c], hqt[p] = hqt[p], hqt[c]
      c = p
    else
      break
    end
  end
end

Heapq.pop = function(self)
  local hqlt = self.lt
  local hqt = self.t
  local ret = hqt[1]
  local c = self.cnt
  hqt[1] = hqt[c]
  c = c - 1
  self.cnt = c
  local p = 1
  while true do
    local d1, d2 = p * 2, p * 2 + 1
    if c < d1 then break
    elseif c < d2 then
      if hqlt(hqt[d1], hqt[p]) then
        hqt[d1], hqt[p] = hqt[p], hqt[d1]
      end
      break
    else
      if hqlt(hqt[d1], hqt[d2]) then
        if hqlt(hqt[d1], hqt[p]) then
          hqt[d1], hqt[p] = hqt[p], hqt[d1]
          p = d1
        else break
        end
      else
        if hqlt(hqt[d2], hqt[p]) then
          hqt[d2], hqt[p] = hqt[p], hqt[d2]
          p = d2
        else break
        end
      end
    end
  end
  return ret
end

Heapq.new = function(lt)
  local obj = {}
  setmetatable(obj, {__index = Heapq})
  obj:create(lt)
  return obj
end

local n, m, x = io.read("*n", "*n", "*n")
local a, b = {}, {}
for i = 1, n do
  a[i], b[i] = io.read("*n", "*n")
end
local t = {}
local pos = {}
for i = 1, m do
  t[i] = {}
  pos[i] = 1
end
for i = 1, n do
  local ai, bi = a[i], b[i]
  table.insert(t[bi], ai)
end
local v = {}
for i = 1, m do
  table.sort(t[i], function(p, q) return p > q end)
  if 0 < #t[i] then
    v[i] = x + t[i][1]
  else
    v[i] = 0
  end
end

local score = {}
local hq = Heapq.new(function(p, q) return v[p] > v[q] end)
for i = 1, m do
  hq:push(i)
end
for i = 1, n do
  local idx = hq:pop()
  score[i] = v[idx]
  pos[idx] = pos[idx] + 1
  if pos[idx] <= #t[idx] then
    v[idx] = t[idx][pos[idx]]
  else
    v[idx] = 0
  end
  hq:push(idx)
end
for i = 2, n do
  score[i] = score[i] + score[i - 1]
end
local ret = 0
local k = io.read("*n")
local c = {}
for i = 1, k do
  c[i] = io.read("*n")
  local ci = c[i]
  if 0 < ci then
    ret = ret + score[ci]
  end
end
ret = tostring(1LL * ret):gsub("LL", "")
print(ret)