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 Input: Context: My first visit to Angkor Wat was in 1980. The country had been at war for many years and _ and falling to pieces. Plants were growing out of the roofs, and trees were growing in the courtyards. Today, the temple is the scene of a busy repair program. A team of 15 Indian experts are organizing a workforce of 400 Cambodians, most of them women, who are cleaning, repairing and rebuilding parts of this temple. As I walked through the courtyards, I noticed the Cambodian women devote hours to cleaning carefully a tiny area of stone. Boards are laid down to protect the precious painted stones while the repair work is going on. There are very few machines and little heavy equipment. Workers carry building materials in buckets at the end of long poles. Piles of stones lie in a corner of the courtyard, waiting to be replaced. The work of cleaning the stones is watched over by three Indian chemists. It is a very slow task. First they clean the stones with brushes using buckets of a weak chemical. Then gaps between the stones are filled in. Finally another material is painted onto the stones which will protect them from water forever. Work starts every day at 7 a. m. and goes on until late afternoon six days a week, with a break at midday. Evening is the best time to visit the temple, after the tour groups have left. As the sun sinks lower, shadows spread across the courtyard. After sunset, the sky turns pink. The grey stone towers take on a golden color before turning pink. Nowhere else in the world can there be such a quiet, beautiful place. 
 Question: To clean the stone, how many steps should be followed?
Example Output: three

Example Input: Context: Previous X-ray crystal structures have shown that linkers of five amino acid residues connecting pairs of chicken brain alpha-spectrin and human erythroid beta-spectrin repeats can undergo bending without losing their alpha-helical structure. To test whether bending at one linker can influence bending at an adjacent linker, the structures of two and three repeat fragments of chicken brain alpha-spectrin have been determined by X-ray crystallography. The structure of the three-repeat fragment clearly shows that bending at one linker can occur independently of bending at an adjacent linker. This observation increases the possible trajectories of modeled chains of spectrin repeats. Furthermore, the three-repeat molecule crystallized as an antiparallel dimer with a significantly smaller buried interfacial area than that of alpha-actinin, a spectrin-related molecule, but large enough and of a type indicating biological specificity. Comparison of the structures of the spectrin and alpha-actinin dimers supports weak association of the former, which could not be detected by analytical ultracentrifugation, versus strong association of the latter, which has been observed by others. To correlate features of the structure with solution properties and to test a previous model of stable spectrin and dystrophin repeats, the number of inter-helical interactions in each repeat of several spectrin structures were counted and compared to their thermal stabilities. Inter-helical interactions, but not all interactions, increased in parallel with measured thermal stabilities of each repeat and in agreement with the thermal stabilities of two and three repeats and also partial repeats of spectrin. 
 Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?
Example Output: antiparallel

Example Input: Context: Both restless legs syndrome ([RLS], also known as Willis-Ekbom Disease [WED]) and depression are common during pregnancy. However, no prior studies have assessed if pregnant women with RLS have an elevated risk of depression during and/or after pregnancy. 1,428 women who were pregnant in gestational week 16-17 were asked to participate in a longitudinal survey. They were followed by web-based questionnaires in gestational week 17 and 32, and 6 weeks after delivery. Data were also retrieved from prenatal and birth records. Two different sets of criteria were used to examine the prevalence of RLS in the cohort (International Restless Legs Syndrome Society Group standard criteria and the later developed CH-RLSQ11 questionnaire). The latter questionnaire attempts to exclude those with common "mimics" of RLS. Adjusted odds ratio for depression in gestational week 17, 32, and postpartum week 6 in relation to pre-pregnancy RLS onset and moderate to severe symptom severity were 4.74 (2.30 - 9.76), 3.67 (1.85 - 7.28), and 2.58 (1.28 - 5.21), respectively. No significant associations were seen in pregnant women with de novo RLS during pregnancy. When using the standard diagnostic RLS criteria and frequency of symptoms more than 2-3 days per week, the prevalence of RLS was 12.3%. With the CH-RLSQ11 questionnaire and the same threshold for frequency of symptoms the prevalence was 6.5%. Women with RLS onset before pregnancy with moderate or severe symptoms had an increased risk of both antenatal and postnatal depression. The self-reported prevalence of RLS during pregnancy is lower when a questionnaire dealing with "mimics" is used. 
 Question: Willis-Ekbom disease is also known as?
Example Output:
restless legs syndrome