#include<bits/stdc++.h>
using namespace std;

// macros
#define int long long 
#define TIME clock() * 1.0 / CLOCKS_PER_SEC
#define all(c) c.begin(), c.end()
#define PB push_back
#define MP make_pair
#define bitcount __builtin_popcount
#define watch(x) cerr<< (#x) << " is " << (x) <<"\n";
#define sz(x) ((int)((x).size()))
#define UNIQUE(c) (c).resize(unique(all(c)) - (c).begin())
#define pii2ll(p) ((ll)(p).first<<32 | (p).second)

// type definitions
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector< vi > vvi;
typedef pair<int, int> pii;
typedef long double ld;

// template functions
template < typename A, typename B >
ostream &operator << ( ostream& os, const pair< A, B > & p ) {
    return os << "(" << p.first << ", " << p.second << ")";
}
template < typename T >
ostream &operator << ( ostream & os, const vector< T > &v ) {
    os << "[";
    typename vector< T > :: const_iterator it;
    for( it = v.begin(); it != v.end(); it++ ) {
        if( it != v.begin() ) os << ", ";
        os << *it;
    }
    return os << "]";
}
template < typename T >
ostream &operator << ( ostream & os, const set< T > &v ) {
    os << "{";
    typename set< T > :: const_iterator it;
    for ( it = v.begin(); it != v.end(); it++ ) {
        if( it != v.begin() ) os << ", ";
        os << *it;
    }
    return os << "}";
}
template < typename A, typename B >
ostream &operator << ( ostream & os, const map< A, B > &v ) {
    os << "[";
    typename map< A, B >::const_iterator it;
    for( it = v.begin(); it != v.end(); it++ ) {
        if( it != v.begin() ) os << ", ";
        os << it -> first << " -> " << it -> second ;
    }
    return os << "]";
}
template<typename T>
T gcd(T a, T b) { if(a==0 or b==0) return a+b; return gcd(b, a%b) ; }
template<typename T>
T lcm(T a, T b) { if(a==0 or b==0) return 0; return a/gcd(a, b)*b; }

// random number generation
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

// constants
const long double eps = LDBL_EPSILON;
const int inf = 1e15;
const int modn = 1e9+7;
const int maxn = 2e5+3;

int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    // Your code here
    string s, t;
    cin>>s>>t;
    int n = s.size(), m = t.size();
    vvi dp(n, vi(m));
    if(s[0]==t[0]) {
        dp[0][0] = 1;
    }
    for(int i=1; i<n; i++) {
        if(s[i]==t[0]) {
            dp[i][0] = 1;
        }
        else {
            dp[i][0] = dp[i-1][0];
        }
    }
    for(int i=1; i<m; i++) {
        if(s[0]==t[i]) {
            dp[0][i] = 1;
        }
        else {
            dp[0][i] = dp[0][i-1];
        }
    }
    for(int i=1; i<n; i++) {
        for(int j=1; j<m; j++) {
            if(s[i]==t[j]) {
                dp[i][j] = 1 + dp[i-1][j-1];
            }
            else {
                dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
            }
        }
    }
    // cout << dp[n-1][m-1] << "\n";

    string ans;
    int i = n-1, j = m-1;
    while(i>=0 and j>=0) {
        if(s[i]==t[j]) {
            ans.PB(s[i]);
            i--, j--;
            continue;
        }
        if(i==0) {
            j--;
        }
        else if(j==0) {
            i--;
        }
        else {
            if(dp[i][j] == dp[i-1][j]) {
                i--;
            }
            else {
                j--;
            }
        }
    }
    reverse(all(ans));
    cout << ans << "\n";
    return 0;
}



Measured memory_bytes: 70784