R Markdown and Leaflet

library(leaflet)

my_map <- leaflet() %>% addTiles() 
my_map <- my_map %>% addMarkers(lat=41.9028, lng= 12.4964, popup="Rome")
my_map <- my_map %>% addMarkers(lat=45.076589, lng= 7.688315, popup="Turin")
my_map <- my_map %>% addMarkers(lat=45.463886, lng= 9.190781, popup="Milan")
my_map