# frozen_string_literal: true
in_n, in_m = gets.chomp.split.map(&:to_i)
in_a = gets.chomp.split.map(&:to_i)

current_start = 0
current_last = -1
segments = []
in_a.each do |a|
  if current_last + 1 == a
    current_last += 1
  else
    segments << [current_start, current_last] if current_last != -1
    current_start = a
    current_last = a
  end
end
segments << [current_start, current_last]

puts segments.size
segments.each { |s, l| puts [s, l - s + 1].join(" ") }