# frozen_string_literal: true
in_n = gets.chomp.to_i
in_a, in_b = gets.chomp.split.map(&:to_i)
in_p = gets.chomp.split.map(&:to_i)
a = in_a
b = in_b

in_p.each_with_index do |p, i|
  if p == 1
    a -= 1
  elsif p == 2
    b -= 1
  elsif p == 3
    a -= 1
    b -= 1
  end

  if a < 0 || b < 0
    puts i + 1
    exit
  end
end
puts -1