# your code goes here
#test= 'abab'
#for i in range(len(test)):
#	for k in range(len(test)-i):
#		print test[i:i+k+1]
def uniq_substring(test):
	lista=[]
	[lista.append(test[i:i+k+1]) for i in range(len(test)) for k in range(len(test)-i) if test[i:i+k+1] not in lista and test[i:i+k+1][::-1] not in lista]
	print lista

uniq_substring('rohit')
uniq_substring('abab')