open System
open System.IO

let solve() = 
    let dt = DateTime.Parse("2015/01/01")
    
    let rec countHappyDay (DT:DateTime) (c:int) =
        let m = DT.Month
        let d = DT.Day

        if m = 12 && d = 31 then
            c
        else
            let l, h = d % 10, (d / 10) % 10
            let DT = DT.AddDays(1.)
            if l + h = m then
                countHappyDay DT (c+1)
            else
                countHappyDay DT c

    countHappyDay dt 0 |> printfn "%d"

[<EntryPoint>]
let main argv = 
    solve()
    0