let input = stdin.ReadLine().Split(' ')
let N = input.[0] |> int
let p = input.[1] |> float

let count = Array.zeroCreate (N+1)
for i = 2 to N do
    for j in i*2 .. i .. N do
        count.[j] <- count.[j] + 1

let p2 = 1.0 - p
[ for i = 2 to N do
    yield if count.[i] = 0 then 1.0 else p2 ** (float count.[i]) ]
|> List.sum
|> printfn "%f"