class UnionFind
  def initialize(size)
    @rank = Array.new(size, 0)
    @parent = Array.new(size, &:itself)
  end

  def unite(id_x, id_y)
    x_parent = get_parent(id_x)
    y_parent = get_parent(id_y)
    return if x_parent == y_parent

    if @rank[x_parent] > @rank[y_parent]
      @parent[y_parent] = x_parent
    else
      @parent[x_parent] = y_parent
      @rank[y_parent] += 1 if @rank[x_parent] == @rank[y_parent]
    end
  end

  def get_parent(id_x)
    @parent[id_x] == id_x ? id_x : (@parent[id_x] = get_parent(@parent[id_x]))
  end

  def same_parent?(id_x, id_y)
    get_parent(id_x) == get_parent(id_y)
  end
end

N,M=gets.split.map &:to_i
as=M.times.map{gets.split.map(&:to_i)}
tree=UnionFind.new(N)
for i in 0...M
    tree.unite(as[i][0]-1,as[i][1]-1)
end
puts (0...N).to_a.map{|x|tree.get_parent(x)}.uniq.size
