L1=['a','b','c','d']
L2=['b','c','d','e']
S1=set(L1)
S2=set(L2)
print("S1: ",S1)
print("S2: ",S2)
print("S1vsS2 ",S1.difference(S2))
print("S2vsS1 ",S2.difference(S1))
cross = set(L1).symmetric_difference(set(L2))