char s1[MAXN], s2[MAXN];
int dp[MAXN][MAXN], path[MAXN][MAXN];
 
void Print(int l1, int l2)
{
    if (l1 == 0 && l2 == 0) return;
    if (path[l1][l2] == 0)
    {
        Print(l1-1, l2-1);
        printf("%c", s1[l1]);
    }
    else if (path[l1][l2] == 1)
    {
        Print(l1-1, l2);
        printf("%c", s1[l1]);
    }
    else
    {
        Print(l1, l2-1);
        printf("%c", s2[l2]);
    }
}
 
int main()
{
    //ROP;
    while (~scanf("%s%s", s1+1, s2+1))
    {
        MS(dp, 0); MS(path, 0);
        int len1 = strlen(s1+1), len2 = strlen(s2+1);
        for (int i = 1; i <= len1; i++) path[i][0] = 1;
        for (int i = 1; i <= len2; i++) path[0][i] = 2;
        for (int i = 1; i <= len1; i++)
            for (int j = 1; j <= len2; j++)
            {
                if (s1[i] == s2[j])
                {
                    dp[i][j] = dp[i-1][j-1]+1;
                    path[i][j] = 0;
                }
                else if (dp[i-1][j] >= dp[i][j-1])
                {
                    dp[i][j] = dp[i-1][j];
                    path[i][j] = 1; //up
                }
                else
                {
                    dp[i][j] = dp[i][j-1];
                    path[i][j] = 2; //left
                }
            }
        Print(len1, len2);
        puts("");
    }
    return 0;
}