Draw an activity diagram for the following scenario:

In an online purchasing system, the buyer requests to buy an item. In parallel, the system looks up whether the item exists in the store and verifies if the buyer has an account with the system. If the buyer does not have an account, the system will ask for registration info from the buyer to open an account. If the buyer does not provide registration info, the system exits. If the item does not exist in the store, the system exits. If the item exists, the system will check if the item price is less than or equal to buyers account balance. If the buyer has enough money in the account to purchase the item, the system completes the purchase order successfully. If the buyer does not have enough money, the system exits.