D = gets.split.map(&:to_i)

D.permutation do |nums|
  ok = true

  nums.each_cons(3) do |a, b, c|
    ok = false if a == b
    ok = false if a == c
    ok = false if b == c
    ok = false if a < b && b < c
    ok = false if a > b && b > c
    ok = false if a > c
  end

  if ok
    puts 'YES'
    exit
  end
end

puts 'NO'