# frozen_string_literal: true

def solve
  tp = TP
  tp.prepend([0, 0])
  tp.each_cons(2).any? { |a, b| (b[0] - a[0]) < (b[1] - a[1]) } ? 'No' : 'Yes'
end

N, M = gets.split.map(&:to_i)
TP = M.times.map { gets.split.map(&:to_i) }

puts solve