Css Nesting problem

Question

plz tell me any one about nesting in css. Nesting in css confusion me.

is this same meaning?
     
#navmenu ul li ul li:hover a:hover{background:#ccc; color:#000; }

                                or
#navmenu ul li:hover ul li a:hover{background:#ccc; color:#000; }

it show me same effect


code here start