**Task:**

* Explain what happens if the number of users doubles
* Write the runtime formula using:

  * `n` = number of users
  * `m` = average username length

**Expected reasoning:**

* Doubling the list doubles the execution time
* Linear runtime: `T(n, m) = n × m`

**Answer**

if the number of user double in size 

$$
T(2n, m) = n /times 2 /times m
$$

so the number of execution will multiply by 2

the big O notation will be O(n⋅m)