The two numbers 9 ** 19 and int(float(9 ** 19)) apparently are two different values. I presume this was due to the conversion to int from float, which reduces/changes the precision of the decimal point. You can easily verify this by printing the two values as follows:
print(9 ** 19, int(float(9 ** 19)))
There you'll see they are different, and as such checking them for equality yields false, which then be stored into variable <a>.