package nowcoder;

import java.util.HashSet;

import java.util.Scanner;

import java.util.Set;

/**

* Created by jacob on 2019-07-24.

*/

public class LCS {

public static void main(String[] args) {

LCS main = new LCS();

Scanner scanner = new Scanner(System.in);

while (scanner.hasNextLine()) {

String[] strings = scanner.nextLine().split(" ");

System.out.println(main.longestCommonSequence(strings[0], strings[1]));

}

}

private Set<String> longestCommonSequence(String a, String b) {

if (a.length() == 0 || b.length() == 0) {

return null;

}

int[][] dp = new int[a.length() + 1][b.length() + 1];

char[] aChars = a.toCharArray();

char[] bChars = b.toCharArray();

for (int i = 0; i < a.length(); i++) {

for (int j = 0; j < b.length(); j++) {

if (aChars[i] == bChars[j]) {

dp[i + 1][j + 1] = dp[i][j] + 1;

} else {

dp[i + 1][j + 1] = Math.max(dp[i][j + 1], dp[i + 1][j]);

}

}

} // 将二维数组的数据全部填充完毕

Set<String> result = new HashSet<>();

this.printCommonSequeue(aChars, bChars, dp, "", result, a.length(), b.length());

return result;

}

private void printCommonSequeue(char[] aChars, char[] bChars, int[][] dp,

String initStr, Set<String> result,

int i, int j) {

StringBuilder stringBuilder = new StringBuilder(initStr);

while (i > 0 && j > 0) {

if (aChars[i - 1] == bChars[j - 1]) {

stringBuilder.append(aChars[i - 1]);

i--;

j--;

} else {

if (dp[i][j - 1] > dp[i - 1][j]) {

j--;

} else if (dp[i][j - 1] < dp[i - 1][j]) {

i--;

} else {

this.printCommonSequeue(aChars, bChars, dp, stringBuilder.toString(), result, i - 1, j);

j--;

}

}

}

result.add(stringBuilder.reverse().toString());

}

}