#include <bits/stdc++.h>

 using namespace std;

 const int N=;

 int dp[N][N],dir[N][N];

 char s1[N],s2[N];

 int n1,n2;

 void m_printf (int x,int y) {

     if (x<=||y<=)  {

         for (int i=;i<=x;i++)

             putchar(s1[i]);

         for (int i=;i<=y;i++)

             putchar(s2[i]);

         return ;

     }

     if (dir[x][y]==) {

         m_printf(x-,y-);

         putchar (s1[x]);

     }

     else if (dir[x][y]>) {

         m_printf(x-,y);

         putchar (s1[x]);

     }

     else {

         m_printf(x,y-);

         putchar (s2[y]);

     }

     return ;

 }

 int main ()

 {

     while (~scanf (" %s %s",s1+,s2+)) {

         memset (dp,,sizeof(dp));

         int n1=strlen(s1+);

         int n2=strlen(s2+);

         for (int i=;i<=n1;i++)

             for (int j=;j<=n2;j++) {

                 if (s1[i]==s2[j]) {

                     dir[i][j]=;

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

                 }

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

                     dir[i][j]=;

                     dp[i][j]=dp[i-][j];

                 }

                 else {

                     dir[i][j]=-;

                     dp[i][j]=dp[i][j-];

                 }

             }

        // printf("%d\n",dp[n1][n2]);

         m_printf(n1,n2);

         printf("\n");

     }

     return ;

 }