#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef string str;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector <pii> vpii;
typedef vector <pll> vpll;
typedef map <str,int> mapsi;
typedef map <str,int> :: iterator mapsitr;
typedef map <int , int> mint;
typedef map <ll , ll> mll;
typedef set <int> si;
typedef set <ll> sll;
typedef si :: iterator sitr;
typedef si :: reverse_iterator rsitr;
typedef sll :: iterator sltr;
typedef sll :: reverse_iterator rsltr;
#define mset multiset

typedef mset <int> msi;
typedef mset <ll> msll;
typedef msi :: iterator msitr;
typedef msi :: reverse_iterator msritr;
typedef msll :: iterator msltr;
typedef msll :: reverse_iterator mslritr;

#define mp make_pair
#define pb push_back
#define pob pop_back
#define pf push_front
#define pof pop_front
#define fi first
#define se second
#define fs first.second
#define ss second.second
#define ff first.first
#define sf second.first
#define newl '\n'

char to_upper (char x){
    if( 97 <= int(x) && int(x) <= 126)return char(x-32);
    else if( 65 <= int(x) && int(x) <= 90)return x;
}
char to_lower (char x){
    if( 97 <= int(x) && int(x) <= 126)return x;
    else if( 65 <= int(x) && int(x) <= 90)return char(x+32);
}
int numerize (char x){
    if(48 <= int(x) && int(x) <= 57)return int(x-'0');
    else if( 97 <= int(x) && int(x) <= 126)return int(x-96);
    else if( 65 <= int(x) && int(x) <= 90)return int(x-64);
}
bool isect (int l1, int r1, int l2, int r2){
    pii p1,p2;
    p1 = mp(l1,r1); p2 = mp(l2,r2);
    if(p1>p2)swap(p1,p2);
    if(p2.fi <= p1.se)return true;
    else return false;
}
ll fexp (ll num1, ll num2, ll MOD){
    if(num2==0)return 1;
    else if(num2==1)return num1;
    else{
        ll temp = fexp (num1,num2/2,MOD); ll res = ((temp%MOD) * (temp%MOD))%MOD;
        if(num2%2==1) res = ((res%MOD)*(num1%MOD))%MOD; return res;
    }
}
ll invmod (ll num, ll MOD){return fexp (num,MOD-2,MOD);}
ll gcd (ll num1, ll num2){
    if(num1 < num2) swap(num1,num2); ll num3 = num1 % num2 ;
    while(num3 > 0){ num1 = num2; num2 = num3; num3 = num1 % num2;}
    return num2;
}
ll lcm (ll num1 , ll num2){return (ll) (num1/gcd(num1,num2))*num2;}

// end of Template

str s,t;
bool calc[3020][3020];
ll lcs [3020][3020];
ll dp (int x, int y){
    if(x<=0 || y<=0)return 0;
    else if(calc[x][y])return lcs[x][y];
    else{
        ll res = 0;
        if(s[x]==t[y]){res = 1 + dp(x-1,y-1);}
        else{
            res = max(dp(x-1,y),dp(x,y-1));
        }
        calc[x][y]=true;
        lcs[x][y]=res;
        return res;

    }
}
str ans;
stack <char> z;
int main(){

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

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin>>s;s=" "+s;
    cin>>t;t=" "+t;

    int i = s.size()-1;
    int j = t.size()-1;

    dp(i,j);
    while(i>0 && j>0){
        if(s[i]==t[j]){
            ans += s[i];
            i--;j--;
        }
        else{
            if(lcs[i-1][j] >= lcs[i][j-1]){
                i--;
            }
            else{
                j--;
            }
        }
    }
    for(int i=0;i<ans.size();i++)z.push(ans[i]);
    while(!z.empty()){cout<<z.top();z.pop();}
    cout<<newl;
}


Measured memory_bytes: 80640