$7\mathrm{.}17$ LAB: Remove all non$-$alpha characters

Write a program that removes all non$-$alpha characters from the given input.

Ex: If the input is:

$-$Hello,$1$ world$$!$

the output is:

Helloworld

$567468\mathrm{.}3946988.qx3zqy7$

LAB

ACTIVITY

$7\mathrm{.}17\mathrm{.}1$: LAB : Remove all non$-$alpha characters

$\frac{3}{10}$