n, m = gets.split.map(&:to_i)

a, v, tmp, ans = [], Array.new(n, 0), 0, nil

n.times do |i|
  a << gets.to_i
end

m.times do |i|
  b = gets.to_i
  
  a.each_index do |j|
    if a[j] <= b
      v[j] += 1
      break
    end
  end
end

v.each_index do |i|
  ans, tmp = i + 1, v[i] if tmp < v[i]
end

puts ans