open Scanf
open Printf

let readint () = scanf " %d" (fun x -> x)
let readstr () = scanf " %s" (fun x -> x)
let readint2 () = scanf " %d %d" (fun x y -> x, y)
let stoa s = Array.init (String.length s) (String.get s)
let atos a = String.init (Array.length a) (Array.get a)

let inf = max_int / 4
let min3 x y z = min x (min y z)

let f (x, y, z) (c, d) =
  let x' = c + min3 (x + c) (y + c + d) (z + d) in
  let y' = c + min x (y + d) in
  let z' = c + min3 (x + c) (y + c + d) (z + d) in
  x', y', z'

let () =
  let n = readint () in
  let _, _, ans = Array.init n (fun _ -> readint2 ())
    |> Array.fold_left f (0, inf, inf) in
  printf "%d\n" ans