let mutable n = - 1
        let delete =
            while (onlyBrackets.Length <> n) do
                n <- onlyBrackets.Length
                onlyBrackets <- onlyBrackets.Replace("()","")
                onlyBrackets <- onlyBrackets.Replace("{}","")
                onlyBrackets <- onlyBrackets.Replace("[]","")

        onlyBrackets = ""