Given the task definition, example input & output, solve the new input case.
Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Example: Context: Architecturally, the school has a Catholic character. Atop the Main Building's gold dome is a golden statue of the Virgin Mary. Immediately in front of the Main Building and facing it, is a copper statue of Christ with arms upraised with the legend 'Venite Ad Me Omnes'. Next to the Main Building is the Basilica of the Sacred Heart. Immediately behind the basilica is the Grotto, a Marian place of prayer and reflection. It is a replica of the grotto at Lourdes, France where the Virgin Mary reputedly appeared to Saint Bernadette Soubirous in 1858. At the end of the main drive (and in a direct line that connects through 3 statues and the Gold Dome), is a simple, modern stone statue of Mary.
Question: To whom did the Virgin Mary allegedly appear in 1858 in Lourdes France?
Output: Saint Bernadette Soubirous
This is the correct answer. Because the question is asking for the name of the person and following sentence from the passage answers it: It is a replica of the grotto at Lourdes, France where the Virgin Mary reputedly appeared to Saint Bernadette Soubirous in 1858.

New input case for you: Context: Clinical features variability between familial and sporadic restless legs syndrome/Willis-Ekbom disease (RLS/WED) has been previously reported. With this retrospective cohort study, we aimed to determine the clinical and polysomnographic characteristics of 400 RLS/WED patients. Patients with familial RLS/WED were significantly younger than sporadic RLS/WED, while clinical and polysomnographic characteristics were similar in both groups. No difference was found for the age-at-onset between idiopathic and secondary RLS/WED. Periodic limb movements (PLM) index and REM sleep time were higher in idiopathic RLS/WED. Time of onset of symptoms was in the evening or at bedtime in 28.04 and 37.80% of patients, respectively, while in 21.34% of patients onset was more than 1 h after sleep onset. Impulse control and compulsive behaviours (ICBs) were found in 13.29% patients on dopamine agonist therapy. Our analyses support the hypothesis that patients with a familial history of RLS/WED may have a genetic component. Nevertheless, the dichotomy between early and late onset disease seems to be less sharp than previously reported. A large proportion of RLS/WED patients can have atypical features, therefore making the diagnosis challenging. Some cases can be missed even when the patient refers to a sleep specialist, as revealed by the partial absence of daytime symptoms, the high comorbidity with insomnia and other sleep complaints and the high percentage of symptoms beginning after sleep onset. This draws attention on the importance of a careful evaluation of the patient, to recognize potentially treatable secondary forms of RLS/WED.
Question: Willis-Ekbom disease is also known as?
Output:
restless legs syndrome