AK
arr.Where(x => arr.Where(y => x == y).Count() == 1).Count()Size: a a a
AK
SB
arr.Where(x => arr.Where(y => x == y).Count() == 1).Count()arr.Select(x=>x).Distinct().Count();AM
arr.Select(x=>x).Distinct().Count();S1
AM
SB
SB
ЕА
arr.Select(x=>x).Distinct().Count();AM
AM
SB
МР
МР
МР
МР
arr.Select(x=>x).Distinct().Count();МР
AM
AM