n, m = gets.split.map &:to_i
eyedrops = m.times.map {gets.split.map &:to_i}
eyedrops = eyedrops.sort_by { |(t, _)| t }
eyedrops.unshift [0, 0]
if (0..m-1).all? { |i| (eyedrops[i+1][1] - eyedrops[i][1]).abs <= (eyedrops[i+1][0] - eyedrops[i][0]) }
    puts :Yes
else
    puts :No
end