Suppose i have $\displaystyle \sum_{n=1}^{\infty} ||f_n||_2 < \infty$. How to show that the $\displaystyle \sum_{n=1}^{\infty} f_n$ converges absoutely almost everywhere ,

f=$\displaystyle \sum_{n=1}^{\infty} f_n \in L^2$ , and $\displaystyle ||f||_2 <= \sum_{n=1}^{\infty}||f_n||_2 $ .