open System
type Sol() =
    member this.Solve() = 
        
        let happyDays m ds = 
            ds |> Seq.filter (fun d -> ((d%10) + (d/10)) = m ) |> Seq.length
        
        let y2015 = [
            (1,[1..31]);
            (2,[1..28]);
            (3,[1..31]);
            (4,[1..30]);
            (5,[1..31]);
            (6,[1..30]);
            (7,[1..31]);
            (8,[1..31]);
            (9,[1..30]);
            (10,[1..31]);
            (11,[1..30]);
            (12,[1..31]) ]
        
        y2015 |> Seq.sumBy (fun (m,ds) -> happyDays m ds ) |> printfn "%d"
        
let mySol = new Sol()
mySol.Solve()