Port-wine birthmarks, which are caused by malformed capillaries close to the skin, can be removed with laser pulses. Laser light of the right color will pass through the skin with little absorption but will be strongly absorbed by oxyhemoglobin in the blood of these capillaries, which destroys them without damaging adjacent tissue. A typical system uses a series of 6900 W pulses of 585 nm laser light. Each pulse lasts 0.45 ms. How many photons are in each pulse?