let scan_int () = Scanf.scanf " %d" (fun x -> x)
let print_int n = Printf.printf "%d\n" n

module Union_find :
  sig
    type t
    val init  : int -> t
    val get   : t -> int -> int
    val find  : t -> int -> int
    val size  : t -> int -> int
    val unite : t -> int -> int -> unit
    val same  : t -> int -> int -> bool
  end =
  struct
    type t = int array
    let init n = Array.make (n+1) (-1)
    let get data x = data.(x)
    let rec find data x =
      if data.(x) < 0 then x
      else let _ = data.(x) <- find data data.(x) in data.(x)
    let size data x = - data.(find data x)
    let unite data x y =
      let x = find data x and y = find data y in
      if x <> y then
        if data.(x) < data.(y) then
          let _ = data.(x) <- data.(x) + data.(y) in
          data.(y) <- x
        else
          let _ = data.(y) <- data.(x) + data.(y) in
          data.(x) <- y
    let same data x y =
      let x = find data x and y = find data y in (x == y)
  end

let () =
  let n = scan_int() in
  let max_n = 100000 in
  let v = Array.make (max_n+1) [] in
  let uf = Union_find.init max_n in
  let _ =
    for i = 1 to n do
      let a = scan_int() and b = scan_int() in
      v.(a) <- b :: v.(a)
    done in
  let _ =
    for i = 1 to max_n do
      if List.length v.(i) > 1 then
        let f x = Union_find.unite uf (List.hd v.(i)) x in
        List.iter f v.(i)
    done in
  let rec calc arr i ret =
    let ret =
      if List.length v.(i) > 0 then ret + Union_find.size uf (List.hd v.(i))
      else ret in
    if i == max_n then ret
    else calc arr (i+1) ret in
  print_int (calc v 0 (-n))