gets.to_i.times do
n = gets.to_i
ans,min = 0, n+1
l = []
n.times do
l << gets.split.map(&:to_i)
end
l = l.sort_by { |e| e[0] }
l.each do |item|
if min > item[1]
ans+=1
min = item[1]
end
end
puts ans
end