Suppose that there are $$ elements labeled according to their current order $(1,2,...,),$ and we permute them $($i$.$e$.$ we reorder them$).$ What is the expected number of elements that will remain in their current location? Store you answer in the variable expected$\_$num$\_$fixed as a float.

Hint: Use the the fact that the expectation of the sum equals the sum of the expectation.