n = gets.to_i
a = Array.new(n+1){|i| i}
gets.to_i.times do
  x, y = gets.split.map(&:to_i)
  a[x], a[y] = a[y], a[x]
end

w = gets.split.map(&:to_i).unshift(0)

ans = []
(n-1).downto(1) do |to|
  for i in 1..to do
    if w[a[i]] > w[a[i+1]] then
      ans << [i, i+1]
      a[i], a[i+1] = a[i+1], a[i]
    end
  end
end

puts ans.size
puts ans.map{|a| a.join(" ")}