如何将sliderinput与selectinput相乘，其中result显示为文本输出

library(shiny)
library(shinydashboard)

ui <- dashboardPage(
  dashboardHeader(title = "SliderInput与SelectInput相乘示例"),
  dashboardSidebar(
    sidebarMenu(
      menuItem("示例", tabName = "example")
    )
  ),
  dashboardBody(
    tabItems(
      tabItem(tabName = "example",
        h2("SliderInput与SelectInput相乘示例"),
        sidebarPanel(
          sliderInput("slider", "滑块输入", min = 1, max = 10, value = 5),
          selectInput("select", "选择输入", choices = c("2", "3", "4"), selected = "2")
        ),
        mainPanel(
          verbatimTextOutput("result")
        )
      )
    )
  )
)

server <- function(input, output) {
  result <- reactive({
    slider_value <- input$slider
    select_value <- as.numeric(input$select)
    slider_value * select_value
  })
  
  output$result <- renderText({
    result()
  })
}

shinyApp(ui = ui, server = server)