How to replace only the first n elements in a numpy array that are larger than a certain value?

I have an array myA like this:

array([ 7,  4,  5,  8,  3, 10])

If I want to replace all values that are larger than a value val by 0, I can simply do:

myA[myA > val] = 0

which gives me the desired output (for val = 5):

 array([0, 4, 5, 0, 3, 0])

However, my goal is to replace not all but only the first n elements of this array that are larger than a value val.

So, if n = 2 my desired outcome would look like this (10 is the third element and should therefore not been replaced):

array([ 0,  4,  5,  0,  3, 10])

A straightforward implementation would be:

import numpy as np

myA = np.array([7, 4, 5, 8, 3, 10])
n = 2
val = 5

# track the number of replacements
repl = 0

for ind, vali in enumerate(myA):

    if vali > val:

        myA[ind] = 0
        repl += 1

        if repl == n:
            break

That works but maybe someone can can up with a smart way of masking!?