local n, p = io.read("*n", "*n")
-- Lua 5.1
local function getyakusuu(x)
  local tmp = {}
  local lim = math.ceil(math.sqrt(x))
  local dv = 2
  while(1 < x and dv <= lim) do
    if(x % dv == 0) then
      tmp[dv] = 1
      x = x / dv
      while(x % dv == 0) do
        x = x / dv
        tmp[dv] = tmp[dv] + 1
      end
    end
    dv = dv + (dv == 2 and 1 or 2)
  end
  if(x ~= 1) then tmp[x] = 1 end
  local cnt = 1
  for k, v in pairs(tmp) do
    cnt = cnt * (v + 1)
  end
  return cnt
end

local tot = 0
for i = 2, n do
  local z = getyakusuu(i) - 2
  if(z == 0) then tot = tot + 1
  else tot = tot + (1 - p)^z end
end
print(string.format("%.8f", tot))