n = read_line.to_i
a, b = read_line.split.map(&.to_i)
p = read_line.split.map(&.to_i)
n.times do |i|
  if p[i] == 1
    a -= 1
  elsif p[i] == 2
    b -= 1
  else
    a -= 1
    b -= 1
  end
  if a < 0 || b < 0
    puts i + 1
    exit
  end
end
puts -1