Python Exponent Question

[databyss]

I have a simple program and the output isn't what I expect.  Could
somebody please explain why?

Here's the code:

#simple program
print "v = 2"
v = 2
print "v**v = 2**2 =", v**v
print "v**v**v = 2**2**2 =", v**v**v
print "v**v**v**v = 2**2**2**2 =", v**v**v**v
#end program

Here's the output:

>>>
v = 2
v**v = 2**2 = 4
v**v**v = 2**2**2 = 16
v**v**v**v = 2**2**2**2 = 65536
>>>

I would expect 2**2**2**2 to be 256