#!/usr/bin/env python

s = input()
t = input()

dp = [[0] * (len(t) + 1) for i in range(len(s) + 1)]

for i in range(len(s)):
    for j in range(len(t)):
        if s[i] == t[j]:
            dp[i + 1][j + 1] = max(dp[i][j] + 1, dp[i + 1][j], dp[i][j + 1])
        else:
            dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1])

ans = ""
i = len(s)
j = len(t)
while i > 0 and j > 0:
    if dp[i][j] == dp[i - 1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j - 1]:
        j -= 1
    else:
        ans += s[i - 1]
        i -= 1
        j -= 1

print(ans[::-1])

e106da2ea044df2dcdfede1d47730e078cd24ec6
<mask token>

<mask token>
for i in range(len(s)):
    for j in range(len(t)):
        if s[i] == t[j]:
            dp[i + 1][j + 1] = max(dp[i][j] + 1, dp[i + 1][j], dp[i][j + 1])
        else:
            dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1])
<mask token>
while i > 0 and j > 0:
    if dp[i][j] == dp[i - 1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j - 1]:
        j -= 1
    else:
        ans += s[i - 1]
        i -= 1
        j -= 1
print(ans[::-1])

s = input()
t = input()
dp = [([0] * (len(t) + 1)) for i in range(len(s) + 1)]
for i in range(len(s)):
    for j in range(len(t)):
        if s[i] == t[j]:
            dp[i + 1][j + 1] = max(dp[i][j] + 1, dp[i + 1][j], dp[i][j + 1])
        else:
            dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1])
ans = ''
i = len(s)
j = len(t)
while i > 0 and j > 0:
    if dp[i][j] == dp[i - 1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j - 1]:
        j -= 1
    else:
        ans += s[i - 1]
        i -= 1
        j -= 1
print(ans[::-1])

#!/usr/bin/env python

s = input()
t = input()

dp = [[0] * (len(t) + 1) for i in range(len(s) + 1)]

for i in range(len(s)):
    for j in range(len(t)):
        if s[i] == t[j]:
            dp[i + 1][j + 1] = max(dp[i][j] + 1, dp[i + 1][j], dp[i][j + 1])
        else:
            dp[i + 1][j + 1] = max(dp[i + 1][j], dp[i][j + 1])

ans = ""
i = len(s)
j = len(t)
while i > 0 and j > 0:
    if dp[i][j] == dp[i - 1][j]:
        i -= 1
    elif dp[i][j] == dp[i][j - 1]:
        j -= 1
    else:
        ans += s[i - 1]
        i -= 1
        j -= 1

print(ans[::-1])
