F# CE from Skeet&Petrichek book

gistfile1.txt

open System

type TheValue<'a> =
    | Value of 'a
    | None
    
let ReadInt()  =
    match  Console.ReadLine() |> Int32.TryParse  with
    | true , v -> Value v
    | _ ->  None

type TheValueBuilder() =
    member x.Bind(v,f) =
        match v with
        | Value v -> f(v)
        | None  -> None
    member x.Return(v) = Value(v)
let value = new TheValueBuilder()    
    
[<EntryPoint>]
    let main argv =
        
        let printTheValue (n:TheValue<int>) =
            match n with
            | Value n -> printfn "%i" n
            | None -> printf "noneValue"
        
        value{            
            let! a = ReadInt() 
            
            Console.WriteLine ("you entered" + a.ToString())
            let! b = ReadInt()
            
            Console.WriteLine ("you entered" + b.ToString())
            let add = a + b           
            return add
        } |> printTheValue
        
        
        Console.WriteLine ("result is above")
        0 // return an integer ex
          // it code