let ``No.26 シャッフルゲーム`` () =
    let N = int <| stdin.ReadLine()
    let M = int <| stdin.ReadLine()
    let rec f s bit =
        if s <= 0 then bit - (bit>>>2)
        else
            let arr =
                stdin.ReadLine().Split(' ')
                |> Array.map int
                |> Array.sort
            let a,b2 = arr.[0],arr.[1]
            let n = b2 - a
            let b = 1 <<< (b2 - 1)
            let c = bit ^^^ (bit &&& (a ||| b))
            f (s-1) ((((bit&&&b)>>>n)|||((bit&&&a)<<<n))|||c)
    f M (1 <<< N - 1)
    |> printfn "%A"
``No.26 シャッフルゲーム`` ()