Existence of a $l_ {\infty} ^*$ element [duplicate]

Exercise: Prove there exist a bounded linear functional $L :l_{ \infty} \rightarrow \mathbb{R}$ such that for every $(x_n)=x \in l _ { \infty }$ $$\lim \mathrm{Inf} (x_n) \leq L(x) \leq \lim \mathrm{Sup} (x_n).$$ My current progress is that should be $L \in l _{ \infty}^*\setminus l_1$. Also I know since $l_1$ is not bidual so there are such functionals. Any help is appreciated.

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marked as duplicate by userNaN, Asaf Karagila, t.b., Davide Giraudo, Ｊ. Ｍ.Jul 10 '12 at 4:06

Not at all ;)${}$ –  userNaN Jul 4 '12 at 18:50