#!/usr/bin/python
# -*- coding: utf-8 -*-

# import
from sys import stdin, setrecursionlimit
setrecursionlimit(10**8)

def int_map():
    return map(int,input().split())

def int_list():
    return list(map(int,input().split()))

def int_mtx(N):
    x = [list(map(int, stdin.readline().split())) for _ in range(N)]
    return x

def str_mtx(N):
    x = [list(stdin.readline()[:-1]) for _ in range(N)]
    return x

def print_space(l):
    return print(" ".join([str(x) for x in l]))



"""    main code    """
N,M = int_map()


def scc(N, G, RG):

    # 一回目のDFS　（順方向のグラフ G を用いる）
    # DFSにおいてスタックから除かれる頂点の順番 order を記録することが目的
    def dfs(s):
        used[s] = 1
        for t in G[s]:
            if not used[t]:
                dfs(t)
        order.append(s)

    # 二回目のDFS　（逆方向のグラフ RG を用いる）
    # 上で得た order を逆順にたどって，行き詰まるまでが一つのグループ扱いになる
    def rdfs(s, label):
        group[s] = label
        used[s] = 1
        for t in RG[s]:
            if not used[t]:
                rdfs(t, label)



    order = []
    used = [0]*N

    # 一回目のDFS    
    for i in range(N):
        if not used[i]:
            dfs(i)
    
    used = [0]*N
    label = 0
    group = [None]*N

    # 二回目のDFS    
    for s in reversed(order):
        if not used[s]:
            rdfs(s, label)
            label += 1
    
    return label, group


# 縮約後のグラフを構築
def construct(N, G, label, group):
    G0 = [set() for i in range(label)]
    GP = [[] for i in range(label)]
    for v in range(N):
        lbs = group[v]
        for w in G[v]:
            lbt = group[w]
            if lbs == lbt:
                continue
            G0[lbs].add(lbt)
        GP[lbs].append(v)
    for i in range(label):
        G0[i] = list(G0[i])

    return G0, GP




UV = []

for _ in range(M):
    a,b,c = int_map()
    UV.append([a-1,b-1])
    UV.append([b-1,a-1])


G = [[] for _ in range(N)]
RG = [[] for _ in range(N)]
for uvi in UV:
    G[uvi[0]].append(uvi[1])
    RG[uvi[1]].append(uvi[0])

####  必ず有向化！！！！  #### 
import pypyjit
pypyjit.set_param('max_unroll_recursion=-1')

label_num, group = scc(N, G, RG)


print(label_num)