How many real roots of the equation x2−18[x]+77=0 are not integer, where [x] denotes the greatest integer not exceeding the real number x?<spanclass=′latex−bold′>(A)</span>0<spanclass=′latex−bold′>(B)</span>1<spanclass=′latex−bold′>(C)</span>2<spanclass=′latex−bold′>(D)</span>3<spanclass=′latex−bold′>(E)</span>None of the preceding