#include <bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(c) (c).begin(),(c).end()
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
#define MINF(a) memset(a,0x3f,sizeof(a))
#define POW(n) (1LL<<(n))
#define IN(i,a,b) (a <= i && i <= b)
using namespace std;
template <typename T> inline bool CHMIN(T& a,T b) { if(a>b) { a=b; return 1; } return 0; }
template <typename T> inline bool CHMAX(T& a,T b) { if(a<b) { a=b; return 1; } return 0; }
template <typename T> inline void SORT(T& a) { sort(ALL(a)); }
template <typename T> inline void REV(T& a) { reverse(ALL(a)); }
template <typename T> inline void UNI(T& a) { sort(ALL(a)); a.erase(unique(ALL(a)),a.end()); }
template <typename T> inline T LB(vector<T>& v, T a) { return *lower_bound(ALL(v),a); }
template <typename T> inline int LBP(vector<T>& v, T a) { return lower_bound(ALL(v),a) - v.begin(); }
template <typename T> inline T UB(vector<T>& v, T a) { return *upper_bound(ALL(v),a); }
template <typename T> inline int UBP(vector<T>& v, T a) { return upper_bound(ALL(v),a) - v.begin(); }
template <typename T1, typename T2> ostream& operator<< (ostream& os, const pair<T1,T2>& p) { os << "(" << p.first << " " << p.second << ")"; return os; }
template <typename T1, typename T2> istream& operator>> (istream& is, pair<T1,T2>& p) { is >> p.first >> p.second; return is; }
template <typename T> ostream& operator<< (ostream& os, const vector<T>& v) { REP(i,v.size()) { if (i) os << " "; os << v[i]; } return os; }
template <typename T> istream& operator>> (istream& is, vector<T>& v) { for(T& in : v) is >> in; return is; }
template <typename T = int> vector<T> make_v(size_t a) { return vector<T>(a); }
template <typename T, typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...)); }
template< typename T, typename V > typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) { t = v; }
template< typename T, typename V > typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) { for(auto &e : t) fill_v(e, v); }
const int MOD = 1000000007;
const int INF = 0x3f3f3f3f3f3f3f3f;
const double EPS = 1e-10;

string LCS_recon(string s, string t) {
  int n = s.size(), m = t.size();
  vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
  vector<vector<pair<int,int>>> pre(n + 1, vector<pii>(m + 1, pair<int,int>(0, 0)));
  for (int i = 1; i <= n; i++) pre[i][0] = make_pair(-1, 0);
  for (int j = 1; j <= m; j++) pre[0][j] = make_pair(0, -1);
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (s[i] == t[j]) {
        dp[i + 1][j + 1] = dp[i][j] + 1;
        pre[i + 1][j + 1] = make_pair(-1, -1);
      } else if (dp[i + 1][j] > dp[i][j + 1]) {
        dp[i + 1][j + 1] = dp[i + 1][j];
        pre[i + 1][j + 1] = make_pair(0, -1);
      } else {
        dp[i + 1][j + 1] = dp[i][j + 1];
        pre[i + 1][j + 1] = make_pair(-1, 0);
      }
    }
  }
  string r;
  int y = n, x = m;
  while (y || x) {
    int dy, dx;
    tie(dy, dx) = pre[y][x];
    if (dy == -1 && dx == -1) r = s[y-1] + r;
    y += dy; x += dx;
  }
  return r;
}

signed main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);

  string s,t;
  cin >> s >> t;
  cout << LCS_recon(s,t) << endl;

  return 0;
}

Measured memory_bytes: 211584