Flexdashboard.storyboard Shiny

How do I add a reactive variable to a storyboard? My code is below

---
title: "Storyboard Page"
output: flexdashboard::flex_dashboard
runtime: shiny
---

```{r}
x<-reactive({input$slider1})

```

Analysis {.storyboard}
=========================================

### Frame 1 `r x`

```{r}
sliderInput("slider1", label = h3("Slider"), min = 0, 
        max = 100, value = 50)
```

      

        
        
        
      

    

Output

Required