open Scanf
open Printf

let id a = a
let pair a b = a, b
let triplet a b c = a, b, c

let rec scan_list = function
  | 1 -> scanf "%d" (fun k -> [k])
  | n -> scanf "%d " (fun k -> k :: scan_list (n-1))

let g arr u v s = arr.(u-1) <- (v-1,s) :: arr.(u-1);
  arr.(v-1) <- (u-1,s) :: arr.(v-1)

let f n m = let graph = (Array.make n []) in
  for i = 1 to m do
    scanf "%d %d %d\n" (g graph)
  done;
  for i = 0 to n-1 do
    graph.(i) <- List.sort compare graph.(i)
  done;
  graph

let h graph ans = let queue = Queue.create () in
  let rec enqueue a = function
    | (v, c) :: lst -> if ans.(v) = 0 then Queue.add (a, v, c) queue; enqueue a lst
    | [] -> ()
  in let rec f () = if Queue.is_empty queue
       then `Ok
       else let (u, v, c) = Queue.take queue
         in if ans.(v) = 0
         then begin
           ans.(v) <- (if c > ans.(u) then c - ans.(u) else raise @@ failwith "negative answer");
           enqueue v graph.(v);
           f ()
         end
         else if c = ans.(v) + ans.(u)
         then begin
           enqueue v graph.(v);
           f ()
         end
         else raise @@ failwith "incorrect"
  in enqueue 0 graph.(0); f()

let cost lst = List.map (function (_, c) -> c) lst
let minimum lst = List.fold_left min 10000000000000 lst

let compute graph = let n = ref 0 in
  for i = 1 to minimum (cost graph.(0)) - 1 do
    let ans = Array.make (Array.length graph) 0
    in ans.(0) <- i;
    match h graph ans with
    | `Ok -> n := !n + 1
    | exception Failure s -> eprintf "%s\n" s
  done;
  printf "%d\n" !n

let () = compute @@ scanf "%d %d\n" f