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

#define NDEBUG
#ifdef DEBUG
#include "../cout11.h"
#undef NDEBUG
#endif
#include <cassert>

#ifdef DEBUG
#define debug(fmt, ...) fprintf(stderr, fmt, __VA_ARGS__)
#else
#define debug(fmt, ...)
#endif

typedef long long ll;
typedef long double Double;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<llll> vllll;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<long double> vD;

#define sz(a)  int((a).size())
#define pb  push_back
#define eb  emplace_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define repC3(vari,varj,vark,n)  for(int vari=0;vari<(n)-2;++vari)for(int varj=vari+1;varj<(n)-1;++varj)for(int vark=varj+1;vark<(n);++vark)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define found(s,e)  ((s).find(e)!=(s).end())
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))
#define cons make_pair

template<class T> inline void amin(T & a, T const & b) { a = min(a, b); }
template<class T> inline void amax(T & a, T const & b) { a = max(a, b); }
template<typename X, typename T> auto vectors(X x, T a) { return vector<T>(x, a); }
template<typename X, typename Y, typename Z, typename... Zs> auto vectors(X x, Y y, Z z, Zs... zs) { auto cont = vectors(y, z, zs...); return vector<decltype(cont)>(x, cont); }


#define UP 1
#define LEFT 2
#define DIAG 3

string solve(string& s, string& t){
    int sl=s.size(), tl=t.size();
    vvi dp(sl+1, vi(tl+1, 0));
    vvi prev(sl+1, vi(tl+1, 0));
    rep1(i,sl) prev[i][0] = UP;
    rep1(i,tl) prev[0][i] = LEFT;

    rep1(i,sl){
        rep1(j,tl) {
            if (s[i-1] == t[j-1]) {
                int curr = dp[i-1][j-1] + 1;
                prev[i][j] = DIAG;
                if (dp[i-1][j] > curr) {
                    curr = dp[i-1][j];
                    prev[i][j] = UP;
                }
                if (dp[i][j-1] > curr) {
                    curr = dp[i][j-1];
                    prev[i][j] = LEFT;
                }
                dp[i][j] = curr;
            } else {
                int curr =  dp[i-1][j];
                prev[i][j] = UP;
                if (dp[i][j-1] > curr) {
                    curr = dp[i][j-1];
                    prev[i][j] = LEFT;
                }
                dp[i][j] = curr;
            }
        }
    }

    int L = dp[sl][tl];
    vector<char> tmp;
    for (int i=sl,j=tl; i>=0 && j>=0; ) {
        switch (prev[i][j]) {
            case LEFT:
                --j; break;
            case UP:
                --i; break;
            case DIAG:
                tmp.pb(s[i-1]);
                --i; --j;
                break;
        }
        if (tmp.size() == L) break;
    }
    reverse(ALL(tmp));
    return  string(ALL(tmp));
}

int main() {
    string s, t; cin >> s >> t;
    cout << solve(s,t) << endl;
    return 0;
}


Measured memory_bytes: 70784