while True:
try:
str_input1, str_input2 = input(), input()
# 区分一下字符串长短
str1 = str_input1 if len(str_input1) <= len(str_input2) else str_input2
str2 = str_input2 if len(str_input1) <= len(str_input2) else str_input1
m = [[0 for i in range(len(str2) + 1)] for j in range(len(str1) + 1)]
# 最长子串的长度
max_sub_len = 0
# 最长子串最后一个字符在str1中的索引位置
p = 0
for i in range(len(str1)):
for j in range(len(str2)):
if str1[i] == str2[j]:
m[i+1][j+1] = m[i][j] + 1
if m[i+1][j+1] > max_sub_len:
max_sub_len = m[i+1][j+1]
p = i
print(str1[p + 1 - max_sub_len: p + 1])
except:
break