def inp() a=gets.chomp.split(" ").map(&:to_i)end 
def inpf() a=gets.chomp.split(" ").map(&:to_f)end
def inps() a=gets.chomp.split(" ")end  
def copy(a) Marshal.load(Marshal.dump(a)) end
def kaizyo(n)(n < 2)? 1 : (2..n).inject(:*) end
def scount(a) b = na(a.max+1); a.each{|n|b[n]+=1};return b end
def na(n,d=0) Array.new(n,d)end
def na2(n,m,d=0) Array.new(n){Array.new(m,d)}end
def na3(n,m,l,d=0) Array.new(n){Array.new(m){Array.new(l,d)}}end
n = inp[0]
c = 0
h = {}
(a = inp).each do |d|
  if h[d] == nil
    h[d] = 1
  else
    h[d] = 2
  end
end
a.each do |d|
  if h[d] == 1
    c  += 1
  end
end
p c