import itertools
A = [2,1,2,3,2,3,4,3,4,5,4,5]
B = [1,0,1]
print([x-y for x, y in itertools.izip(A, itertools.cycle(B))])
aW1wb3J0IGl0ZXJ0b29scwoKQSA9IFsyLDEsMiwzLDIsMyw0LDMsNCw1LDQsNV0KQiA9IFsxLDAsMV0KCnByaW50KFt4LXkgZm9yIHgsIHkgaW4gaXRlcnRvb2xzLml6aXAoQSwgaXRlcnRvb2xzLmN5Y2xlKEIpKV0p
[1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4]