$5\mathrm{.}16$ LAB: Count input length without spaces, periods, exclamatio points, or commas

Given a line of text as input, output the number of characters excluding spaces, periods, exclamation points, or commas.

Ex: If the input is:

Listen, Mr$.$ Jones, calm down.

the output is:

$21$

In python

This is an intro class so code needs to be very basic last listed answer did not work