library(shiny)
shinyUI(pageWithSidebar(
  headerPanel("Hello, Shiny!"),
  sidebarPanel(
    sliderInput(
      "obs",
      "Number of observations:",
      min = 1,
      max = 1000,
      value = 500
    )
  ),
  mainPanel(
    plotOutput("distPlot")
  )
))