Let S ={1,2,3,5,7,10,11}. The number of non-empty subsets of S that have the sum of all elements a multiple of 3, is ____.

Let $\displaystyle \mathrm{S}=\{1,2,3,5,7,10,11\}$. The number of non-empty subsets of S that have the sum of all elements a multiple of $\displaystyle 3$ , is $\displaystyle \_\_\_\_$.