The problem is how to invert alternate bits of a number, starting from the LSB. Currently what I am doing is first doing a

count = -1
while n:
   n >>= 1
   count += 1

to first find the position of the leftmost set bit, then running a loop to invert every alternate bit:

i = 0
while i <= count:
 num ^= 1<<i
 i += 2

Is there a quick hack solution instead of this rather boring loop solution? Of course, the solution can't make any asumption about the size of the integer.