linq with groupby giving syntax error

var stat = (from s in _context.Subjects
join a in _context.Attendances on s.Code equals a.Code
where ((((a.Atten.Count(x => x == '1') * 100) / a.Atten.Length) > scutoff) && s.SemId.Contains(filtsemid))
into sstat select new Stat {
Code = sstat.Code, Name = sstat.Name, SemId = sstat.SemId, Shortage = sstat.Count() })
.GroupBy(s => new { Code = s.Code, Name = s.Name, SemId = s.SemId })
.AsNoTracking();