align action button to right of input box r shiny

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I would like to add an action button right to the input box so that the user can click it and get extra information about what value to provide in the input box. here's an example code (This code puts the action button on the left).
How should I align the action button right to box? Any help would be appreciated!

library(shiny) if (interactive()) { library(shinyBS) ui <- fluidPage( sidebarLayout( sidebarPanel( div(style="display:inline-block;vertical-align:top;", fluidRow( column(4, br(), bsButton("q1", label = "click for more info", icon = icon("question"), style = "info", size = "extra-small")), column(8, fileInput("file", "Upload File *", accept = ".txt")) )), bsPopover(id = "q1", title = "data", content = "more info", placement = "right", trigger = "click", options = NULL) ), verbatimTextOutput ("text") ) ) server <- function(input, output,session) ({ }) shinyApp (ui, server) }