import java.util.Scanner;

/**
 * HJ65 查找两个字符串a,b中的最长公共子串-中等
 */
public class HJ065 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            String s1 = sc.nextLine();
            String s2 = sc.nextLine();
            String maxSubStr = getMaxSubStr2(s1, s2);
            System.out.println(maxSubStr);
        }
        sc.close();
    }

    private static String getMaxSubStr2(String s1, String s2) {
        String longStr = s1.length() > s2.length() ? s1 : s2;
        String shortStr = s1.length() <= s2.length() ? s1 : s2;
        String maxSubStr = "";
        for (int i = 0; i < shortStr.length(); i++) {
            for (int j = 0; j < i + 1; j++) {
                String subStr = shortStr.substring(j, shortStr.length() - i + j);
                if (longStr.contains(subStr)) {
                    return subStr;
                }
            }
        }
        return maxSubStr;
    }
}