def?frequency(s1,?s2):
	count?=?0
	while?s1:
		if?s1.find(s2)?==?-1:
			break
		count?+=?1
		s1?=?s1[s1.find(s2)?+?len(s2):]
	return?count
if?__name__?==?'__main__':
	s1?=?"xxxxbobobxxxx"
	s2?=?"bob"
	print("%s?occurs?%d?times?in?%s"?%?(s2,?frequency(s1,?s2),?s1))

#已經解決了
def?finds(s1,?s2):
????i?=?0
????count?=?0
????while(i<len(s2)?-?len(s1)?+?1):
????????if(s1?==?s2[i:i+3]):
????????????count+=1
????????i+=1
????return?count

s1?=?'bob'
s2?=?'azcbobobegghakl'
print?("Number?of?times?bob?occurs?is:?"+str(finds(s1,?s2)))