Your code fails for cases like n = 2, m = 2 whereby the correct answer is 0, but your code returns INVALID

gracias
estaba perdido
las funciones no las agarra

The arc intesects with the top-right and bottom-left of the square which can only happen if the length of a side on the square and the radius of the circle is equal.

Easiest way to see it is to imagine you had 4 of the same tiles in different orientation so that the arc makes a circle. You can see that the radius of that circle is the same length as the side of the square.

"for" loops are the fastest. Any other function does that internally anyway.