while True: try: s1 = input() s2 = input() index = len(s2) result = '' #结果，动态判断替换 if len(s1) < len(s2): s1,s2 = s2,s1 #s1存长的，s2存短的 for a in range(len(s1)): for b in range(a+1,len(s1)): x = s1[a:b] #子串 if x in s2: if len(x) > len(result):
result=x index = s2.find(x) elif len(x) == len(result) and s2.find(x) < index: #字串长度一样，判断出现的位置在前面才替换 result = x index = s2.find(x) print(result) except: break