Write a function to find the square root of a number. Write a while loop that, starting with 2, tests possible square roots in ascending order by squaring the value and comparing it to n. Return the value that, when squared, is as close as possible to n without going over it. For example, to find the square root of 16, the function will first find 2**2, which is 4. Next, it will find 3**2, which is 9. Finally, it will find 4**2, which is 16, so it will return 4. Finding the square root of 15 is similar but not identical. The function first finds 2**2, which is 4, so it next tries 3**2. That is 9, so it tries 4**2. Since 16 is greater than 15, it stops. But since it is greater than the target value, it returns 3 instead of 4.