#include <cstring>
#include <cassert>
#include <utility>
#include <iostream>
#include <cstdio>
#include <iomanip>
#include <bitset>
#include <chrono>
#include <cstdlib>
#include <functional>
#include <tuple>
#include <climits>
#include <limits>
#include <deque>
#include <list>
#include <array>
#include <stack>
#include <queue>
#include <random>
#include <complex>
#include <string>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define ll              long long
#define pi              pair<int,int>
#define pll             pair<ll,ll>
#define pb              push_back
#define F               first
#define S               second
#define vi              vector<int>
#define vll             vector<ll>
#define endl            '\n'
#define all(v)          (v).begin(),(v).end()
#define FOR(i,a,b)      for(int i=a;i<b;i++)
#define MP(a,b)         make_pair(a,b)
#define debug(x)        cerr<< #x << " : " << x << endl;
#define debugp(p)       cerr<< #p << " : " << "(" << (p).first << "," << (p).second << ")\n";
#define debugv(v)       cerr<< #v << " : " << "["; for(int i = 0; i < (v).size(); i++) cerr << v[i] << " "; cerr<<"]\n";
#define debugs(m)       cerr<< #m << " : [ "; for(auto itr = m.begin(); itr != m.end(); itr++) cerr <<*itr << " "; cerr << "]\n";
#define debugm(m)       cerr<< #m << " : [ "; for(auto itr = m.begin(); itr != m.end(); itr++) cerr <<"(" << itr->first << "," << itr->second << ") "; cerr << "]\n";

/* ordered set: 
tree<T, null_type,less<T>, rb_tree_tag,tree_order_statistics_node_update>
member functions :
1. order_of_key(k) : number of elements strictly lesser than k
2. find_by_order(k) : k-th element in the set
*/

inline ll modexp(ll x, ll ex , ll md) {
    ll ans = 1ll;
    while (ex > 0) {
        if (ex & 1ll) ans = (ans * x) % md;
        ex >>= 1ll;
        x = (x * x) % md;
    }
    return ans;
}

const int inf = 1e9 + 7;

void solve(){
    string s , t;
    cin >> s >> t;
    int n = int (s.length());
    int m = int (t.length());
    s = "$" + s + "%";
    t = "$" + t + "&";

    vector<vector<int>> dp (n + 2 , vector<int> (m + 2, 0));
    vector<vector<int>> x (n + 2 , vector<int> (m + 2, 0));
    vector<vector<int>> y (n + 2 , vector<int> (m + 2, 0));


    // dp[i][j] = is the maximum length of the subsequence formed by prefix of length i of s and prefix
    // of length j of string t

    for (int i = 0; i <= n; i++){
        for (int j = 0; j <= m; j++){
            if (s[i + 1] == t[j + 1]){
                if (dp[i][j] + 1 > dp[i + 1][j + 1]){
                    dp[i + 1][j + 1] = dp[i][j] + 1;
                    x[i + 1][j + 1] = i;
                    y[i + 1][j + 1] = j; 
                }
            }
            if (dp[i][j] > dp[i + 1][j]){
                dp[i + 1][j] = dp[i][j];
                x[i + 1][j] = i;
                y[i + 1][j] = j;
            }
            if (dp[i][j] > dp[i][j + 1]){
                dp[i][j + 1] = dp[i][j];
                x[i][j + 1] = i;
                y[i][j + 1] = j;
            }
        }
    }
    // for (int i = 1; i <= n; i++){
    //     for (int j = 1; j <= m; j++){
    //         cout << dp[i][j] << " ";
    //     }
    //     cout << endl;
    // }
    if (dp[n][m] == 0){
        return;
    }
    string ans = "";
    int st = n;
    int en = m;
    int it = 0;

    while (st != 0 && en != 0){
        if (x[st][en] == st - 1 && y[st][en] == en - 1){
            ans += s[st];
        }
        int st1 = st;
        st = x[st][en];
        en = y[st1][en]; 
    }
    reverse (all (ans));
    cout << ans << endl;
}
int main(){
    ios :: sync_with_stdio(false); 
    cin.tie(nullptr); 
    cout.tie(nullptr);
    
    int T = 1;
    // cin >> T;
    for(int tc = 1; tc <= T; tc++){
        // cout << "Case #" << tc << ": ";
        solve();
    }
    #ifdef LOCAL
    cerr << "Time elapsed\t: " << 1000 * ((double)clock()) / (double)CLOCKS_PER_SEC << "ms\n";       
    #endif
}



Measured memory_bytes: 108968