Given the task definition and input, reply with output. In this task, you have to identify the named entities (NER) which are the ingredients required given its directions. Named entities are the names of the items without their quantity.

Boil potatoes with skin on until done, approximately 20 minutes., Peel off potato skin, if desired, while still warm. Bring eggs to a boil, remove from heat and let stand in hot water 20 minutes., Peel eggs under cold water., Mix cut up potatoes, eggs, onion and celery., For dressing, mix vinegar Miracle Whip, mustard, sugar, salt and pepper., Mix with potato mixture. Refrigerate., Let mixture blend for several hours before serving. (1 potato = approx. 2 servings., Adjust amount as needed.)
egg, onion, celery, vinegar, Miracle Whip, mustard, sugar, salt