let f (str:string) =
    let mutable s =
        str.ToCharArray()
        |> Array.map (fun x -> match x with
                                | '3' -> 'e'
                                | '0' -> 'o'
                                | '1' -> 'l'
                                | '7' -> 'r'
                                | _   ->  x)
    for i = 0 to s.Length - 1 do
        match s.[i] with
        | '|'  -> if s.[i+1] = '-' then
                     s.[i]   <- 'H'
                     for j in [1..2] do s.[i+j] <- '='
                  if s.[i+1] = ')' then
                     s.[i]   <- 'd'
                     s.[i+1] <- '='
        | '\\' -> s.[i] <- 'W'
                  for j in [1..3] do s.[i+j] <- '='
        | _    -> ()
    s
    |> Array.filter ((<>)'=')


open System
Console.WriteLine(f "|-|3110 \/\/071|)")