novelty = Array.new(10001, 0)
n = gets.to_i
data = gets.split.map(&:to_i)
n.times{|i|
    novelty[data[i]] = novelty[data[i]] + 1
}

ans = 0
10000.times{|i|
    if novelty[i]==1
        ans = ans + 1
    end
}
puts ans