// Slower C++ solution:
#include <bits/stdc++.h>

#define ll long long

#define ld long double

#define ull unsigned ll

#define ioi exit(0);

 

#define f first

#define s second

 

#define inf (int)1e9 + 7

 

#define NFS ios_base :: sync_with_stdio(0), cin.tie(0), cout.tie(0);

 

#define mp(x,y) make_pair(x,y)

 

#define lb(x) lower_bound(x)

#define ub(x) upper_bound(x)

 

#define pb push_back

#define ppb pop_back

 

#define bitcoin __builtin_popcount

 

#define endl "\n"

 

#define in(x) insert(x)

 

#define sz(x) (int)x.size()

 

#define all(x) x.begin(),x.end()

 

#define pw2(x) (1ll<<x) //2^x

 

#define forit(it,v) for (typeof(v.begin()) it = v.begin(); it != v.end(); ++it)

 

#define sqr(x) ((x) * 1ll * (x))

 

#define UpdateRandom srand (time(NULL));

 

using namespace std;

 

const int N = (int)3e3 + 7, MOD = (int)1e9 + 7;



string s,t;



string dp[4][N];



int main(){

		

	NFS



	cin >> s >> t;



	for(int i=1;i<=sz(s);i++){

		for(int j=1;j<=sz(t);j++){

			if(sz(dp[2][j-1])>sz(dp[2][j]))dp[2][j]=dp[2][j-1];

			if(sz(dp[2-1][j])>sz(dp[2][j]))dp[2][j]=dp[2-1][j];

			if(sz(dp[2-1][j-1])>sz(dp[2][j]))dp[2][j]=dp[2-1][j-1];

			if(s[i-1]==t[j-1]){

				if(sz(dp[2-1][j-1])+1>sz(dp[2][j]))dp[2][j]=dp[2-1][j-1]+s[i-1];

			}

		}

		for(int j=1;j<=sz(t);j++)dp[1][j]=dp[2][j],dp[2][j].clear();

	}

	

	cout << dp[1][sz(t)] << endl;

	

	ioi

}

// Faster C++ solution for the same problem (measured speedup: 1.3879657166717332x):
#include <ext/pb_ds/assoc_container.hpp>

#include <ext/pb_ds/tree_policy.hpp>

#include <functional>

#include<bits/stdc++.h>

using namespace std;

using namespace __gnu_pbds;





typedef tree<int, null_type, less_equal<int>, rb_tree_tag,

             tree_order_statistics_node_update>

    ordered_set;





#define pf                  printf

#define sf(a)               scanf("%d",&a)

#define sfl(a)              scanf("%lld",&a)

#define sff(a,b)            scanf("%d %d",&a,&b)

#define sffl(a,b)           scanf("%lld %lld",&a,&b)

#define sfff(a,b,c)         scanf("%d %d %d",&a,&b,&c)

#define sfffl(a,b,c)        scanf("%lld %lld %lld",&a,&b,&c)

#define sffff(a,b,c,d)      scanf("%d %d %d %d",&a,&b,&c,&d)

#define sffffl(a,b,c,d)     scanf("%lld %lld %lld %lld",&a,&b,&c,&d)

#define sfffff(a,b,c,d,e)   scanf("%d %d %d %d %d",&a,&b,&c,&d,&e)

#define sfffffl(a,b,c,d,e)  scanf("%lld %lld %lld %lld %lld",&a,&b,&c,&d,&e)

#define sfc(a)              scanf("%c",&a)

#define pii                 pair<int,int>

#define ms(a,b)             memset(a,b,sizeof(a))

#define pb(a)               push_back(a)

#define pbp(a,b)            push_back({a,b})

#define db                  double

#define ft                  float

#define ll                  long long

#define ull                 unsigned long long

#define pii                 pair<int,int>

#define ff                  first

#define ss                  second

#define sz(x)               x.size()

#define all(x)              x.begin(),x.end()

#define CIN                 ios_base::sync_with_stdio(0); cin.tie(0)

#define max3(a, b, c)       max(a, b) > max(b, c) ? max(a, b) : max(b, c)

#define min3(a, b, c)       min(a, b) < min(b, c) ? min(a, b) : min(b, c)

#define for0(i,n)           for(int i=0;i<n;i++)

#define for1(i,n)           for(int i=1;i<=n;i++)

#define forrev(i,n)         for(int i=n-1; i>=0; i--)

#define forab(i,a,b)        for(int i=a;i<=b;i++)

#define forba(i,b,a)        for(int i=b;i>=a;i--)

#define stlloop(x)          for(__typeof(x.begin()) it=x.begin();it!=x.end();it++)

#define gcd(a, b)           __gcd(a, b)

#define lcm(a, b)           ((a)*((b)/gcd(a,b)))

#define case1(z)            cout<<"Case "<<z<<": "

#define case2(z)            printf("Case %d: ",z)

#define PI                  acos(-1) //3.14159265358979323846264338328

#define valid(tx,ty)        tx>=0 && tx<row && ty>=0 && ty<col

#define intlim              2147483648

#define N                   200005

#define inf                 100000008

#define mod                 1000000007



/*------------------------------Graph Moves----------------------------*/

//const int fx[]={+1,-1,+0,+0};

//const int fy[]={+0,+0,+1,-1};

//const int fx[]={+0,+0,+1,-1,-1,+1,-1,+1};   // Kings Move

//const int fy[]={-1,+1,+0,+0,+1,+1,-1,-1};  // Kings Move

//const int fx[]={-2, -2, -1, -1,  1,  1,  2,  2};  // Knights Move

//const int fy[]={-1,  1, -2,  2, -2,  2, -1,  1}; // Knights Move

/*---------------------------------------------------------------------*/



ll c[3005][3005];

char b[3005][3005];







void print_lcs(string s,ll i,ll j)

{

    if(i==0 || j==0)

        return;

    else if(b[i][j]!='<' && b[i][j]!='^')

    {

        print_lcs(s,i-1,j-1);

        cout<<b[i][j];

    }

    else if(b[i][j]=='^') print_lcs(s,i-1,j);

    else if(b[i][j]=='<') print_lcs(s,i,j-1);



}





int main()

{

    ios_base :: sync_with_stdio(0); cin.tie(0); cout.tie(0);

    //freopen("input.txt","r",stdin);

    //freopen("output.txt","w",stdout);

    char s[3005],t[3005];

    string p,q;

    cin>>p>>q;

    ll i,j,ls,lt;

    ls=p.length();

    lt=q.length();

    for(i=0;i<ls;i++)

        s[i+1]=p[i];

    for(i=0;i<lt;i++)

        t[i+1]=q[i];

    for(i=0;i<=ls;i++) c[0][i]=0;



    for(i=0;i<=lt;i++) c[i][0]=0;



    for(i=1;i<=lt;i++)

    {

        for(j=1;j<=ls;j++)

        {

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

            {

                c[i][j]=c[i-1][j-1]+1;

                b[i][j]=s[j];

            }

            else if(c[i-1][j]>=c[i][j-1])

            {

                c[i][j]=c[i-1][j];

                b[i][j]='^';

            }

            else

            {

                c[i][j]=c[i][j-1];

                b[i][j]='<';

            }

        }

    }

    /*for(i=1;i<=lt;i++)

    {

        for(j=1;j<=ls;j++)

            cout<<b[i][j]<<" ";

        cout<<endl;

    }*/

    print_lcs(s,lt,ls);

    cout<<endl;

	return 0;

}