open System

let dprintfn fmt = Printf.kprintf Diagnostics.Debug.WriteLine fmt

let primes n =
    let mid = float n |> sqrt |> floor |> int
    let table = Array.init (n+1) (fun _ -> true)
    seq {
        for i in 2 .. mid do
            if table.[i] then
                yield i
                for j in (i+i) .. i .. n do
                    table.[j] <- false
        for i in (mid+1) .. n do
            if table.[i] then
                yield i
    }

let sum_digit n =
    let rec f acc i =
        let m = i % 10
        let d = i / 10
        let acc' = acc+m
        if d = 0 then
            if acc' < 10 then acc'
            else f 0 acc'
        else
            f acc' d
    f 0 n

[<EntryPoint>]
let main argv = 
    let K = Console.ReadLine() |> int
    let N = Console.ReadLine() |> int

    primes N
    |> Seq.filter (fun x -> x >= K)
    |> Seq.toArray
    |> fun ps ->
        let hash = Array.map sum_digit ps
        let rec loop ans maxcnt j =
            if j = hash.Length then ans else
            let rec f s i =
                if i = hash.Length || Set.exists ((=) hash.[i]) s then s.Count
                else f (Set.add hash.[i] s) (i+1)
            let cnt = f Set.empty j
            if cnt >= maxcnt then
                loop ps.[j] cnt (j+1)
            else 
                loop ans maxcnt (j+1)
        loop 0 0 0

    |> printfn "%d"
    0