local n, p = io.read("*n", "*n")
local a = {}
for i = 1, n do
  a[i] = io.read("*n")
end
table.sort(a)
local v = p
local ans = 0
while v <= a[n] do
  local t = {}
  for i = 1, n do
    local ai = a[i] % v
    if t[ai] then
      ans = ans + t[ai]
      t[ai] = t[ai] + 1
    else
      t[ai] = 1
    end
  end
  v = v * p
end
print(ans)