z = var('z')
y = var('y')
in1 = integral(3*z**2, y, 0, 4)
fp = integral(in1, z, 0, 3)
print "First half: ",fp
in2 = integral(6,z, 0, 3)
fp1 = integral(in2, x, 0, 2)
print "Second half: ",fp1
print "Final Result ",fp-fp1