#include <iostream>
#include <string>
using namespace std;

int main()
{
        string str1, str2;
        cin >> str1 >> str2;
        if (str1 == str2)
        {
                cout << str1;
                return 0;
        }
        int N,N2;
        if (str1.length() > str2.length())
        {
                N = str2.length();
                swap(str1, str2);
        }
        else N = str1.length();

        N2 = str2.length();

        int maxCount = 0, ind1 = 0, ind2 = 0, start = 0, finish = 0;

        while (ind1 != N - 1)
        {
                if (maxCount == N - 1) break;

                if (str1[ind1] == str2[ind2])
                {
                        int tmpStart = ind1, tmp1 = ind1 + 1, tmp2 = ind2 + 1, count = 1, barr = ind1, tmpFinish = ind1;

                        while (barr != N - 1)
                        {

                                if (str1[tmp1] == str2[tmp2])
                                {
                                        count++;
                                        tmpFinish = tmp1;
                                        tmp1++;
                                        tmp2++;
                                        barr++;

                                }
                                else
                                {
                                        if (count > maxCount)
                                        {
                                                maxCount = count;
                                                start = tmpStart;
                                                finish = tmpFinish;
                                        }
                                        count = 0;
                                        ++ind2;
                                        break;
                                }
                                if (count > maxCount)
                                {
                                        maxCount = count;
                                        start = tmpStart;
                                        finish = tmpFinish;
                                }
                                if (barr == N - 1) ++ind2;
                        }

                }
                else ++ind2;

                if (ind2 == N2)
                {
                        ind2 = 0;
                        ++ind1;
                }

        }
        /*if (maxCount == 1) cout << str1[start];
        else {
                do
                {
                        cout << str1[start];
                        start++;
                        maxCount--;
                } while (start <= finish);
        }*/

        if (maxCount != 1)
        {
                do
                {
                        cout << str1[start];
                        start++;
                } while (start <= finish);
        }
        else cout << str1[start];
        return 0;
}