D = gets.split.map(&:to_i)
ans = if D.permutation.any? {|d|
           (0..4).all? {|i|
             d[i] < d[i + 2] && (d[i + 1] > d[i + 2] || d[i + 1] < d[i])}}
        "YES"
      else
        "NO"
      end
puts ans