let distance' = distance (34, 78) (67, -45)
printfn "%3.2f" distance'

#light
open System

let distance p1 p2 =
match (p1, p2) with
| (p1x, p1y), (p2x, p2y) -> Math.Sqrt((float p2x - float p1x) * (float p2x - float p1x) + (float p2y - float p1y) * (float p2y - float p1y))

let distance' = distance (34, 78) (67, -45)
printfn "%3.2f" distance'