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.

Context: The Narym River is a river in the Eastern Kazakhstan, a tributary of the Irtysh River, originating at the junction of the ridges Narym and Sarymsakty of wetland formed by the mountain runoff streams.
Question: The body of water that Narym River is near is what?
irtysh river

Context: As of the 2010 United States Census, there were 1,951,269 people, 715,365 households, and 467,916 families residing in the county. The population density was . There were 840,343 housing units at an average density of . The racial makeup of the county was 60.9% white, 10.5% black or African American, 8.7% Asian, 0.7% Pacific islander, 0.7% American Indian, 13.5% from other races, and 5.1% from two or more races. Those of Hispanic or Latino origin made up 29.1% of the population. In terms of ancestry, 11.7% were Germans, 9.1% were Irish people, 7.6% were English people, 6.3% were Italians, and 2.7% were Americans.
Question: Which group from the census is larger: white or African American?
white

Context: To elucidate the phenotype, genotype, and MRI findings of Korean patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and mutation carriers. The authors studied 40 members of nine unrelated Korean CADASIL families. After genetic analysis of Notch3, clinical and MRI findings were correlated in 27 mutation carriers. Notch3 mutation sites were C174R (one family, n = 3), R133C (one family, n = 3), R587C (one family, n = 1), R544C (two families, n = 5), and R75P (four families, n = 15). The clinical features were typical of CADASIL, but the frequency of migraine in the Korean population appears low. MRI abnormalities were found in 54% of the mutant carriers, the most common being white matter hyperintensities. The prevalence of lacunes and microbleeds increased with patient age. Anterior temporal areas were less often involved in subjects with R75P mutations than in those where mutations occurred in other sites (p = 0.02). Gradient echo imaging identified microbleedings in 33% of mutation carriers (64% of those with abnormal MRI), whereas diffusion-weighted MRI showed abnormal findings in only one patient. Neurologic disability was related to the number of lacunar infarcts and the lesion volume of white matter hyperintensities (p < 0.001) whereas MMSE score was related to the number of lacunar infarcts (p < 0.005). Although Korean cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) mutation carriers show similar clinical and MRI findings, these abnormalities appear less frequently than in other populations. Relatively frequent microbleedings on gradient echo imaging suggest that treatment should be individualized according to MRI findings. The novel mutation of R75P, not involving a cysteine residue, is related to less frequent involvement of the anterior temporal area, thus broadening the spectrum of CADASIL.
Question: Which amino acid residue appears mutated in most of the cases reported with cadasil syndrome?
cysteine