local mmi, mma = math.min, math.max
local mfl, mce = math.floor, math.ceil
local n, d, t = io.read("*n", "*n", "*n")
local rem = {}
local bias = 1000000007
for i = 1, n do
  local x = bias + io.read("*n")
  local r = x % d
  if not rem[r] then rem[r] = {} end
  local z = mfl(x / d)
  table.insert(rem[r], {z - t, z + t})
end
local ret = 0
for _u, tbl in pairs(rem) do
  table.sort(tbl, function(a, b) return a[1] < b[1] end)
  ret = ret + tbl[1][2] - tbl[1][1] + 1
  local right = tbl[1][2]
  for i = 2, #tbl do
    local l, r = tbl[i][1], tbl[i][2]
    l = mma(l, right + 1)
    ret = ret + mma(0, r - l + 1)
    right = mma(right, r)
  end
end
print(ret)