r shiny filter with slider

Question

R shiny app. Trying to filter data using a slider bar. Top line in the ui section, bottom line in the server function

sliderInput("year", "Year", min = 1980, max = 2020, value = 1980)

df <- reactive(filter(games, games$Year == input$year))

App starts up, displays slider but does not display graph. Instead I get "Error: data must be a data frame, or other object coercible by fortify(), not a character vector".

The original data is a data frame