#include <bits/stdc++.h>

using namespace std;

const double EPS = 1e-;

const int INF = 0x3f3f3f3f;

const int mod = 1e9 + ;

const int maxn =  + ;

char s[maxn], t[maxn];

int slen, tlen;

int dp[maxn][maxn], p[maxn][maxn];

void LCS()

{

    memset(dp, , sizeof(dp));

    for(int i = ; i <= slen; i++) p[i][] = ;

    for(int i = ; i <= tlen; i++) p[][i] = -;

    for(int i = ; i <= slen; i++){

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

            if(s[i] == t[j]){

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

                p[i][j] = ;

            }

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

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

                p[i][j] = ;

            }

            else{

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

                p[i][j] = -;

            }

        }

    }

}

void PrintLcs(int i, int j)

{

    if(!i && !j) return ;

    if(p[i][j] == ){

        PrintLcs(i-, j-);

        putchar(s[i]);

    }

    else if(p[i][j] == ){

        PrintLcs(i-, j);

        putchar(s[i]);

    }

    else if(p[i][j] == -){

        PrintLcs(i, j-);

        putchar(t[j]);

    }

}

int main()

{

    while(scanf("%s%s", s + , t + ) != EOF){

        slen = strlen(s + );

        tlen = strlen(t + );

        LCS();

        PrintLcs(slen, tlen);

        puts("");

    }

    return ;

}