/*
 * zyrch - Rupanshu Yadav
 */
#ifdef CREED 
#include "creed.h"
#else
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <fstream>
#include <queue>
#include <deque>
#include <bitset>
#include <iterator>
#include <list>
#include <stack>
#include <map>
#include <set>
#include <functional>
#include <utility>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <cassert>
#include <sstream>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#endif


using namespace std;

typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<ld> vd;
typedef vector<str> vs;
typedef vector<pi> vpi;
typedef vector<pl> vpl;

#define fast_cin() ios_base::sync_with_stdio(false); cin.tie(NULL) 

#define forn(i,a,b) for (int i = (a); i < ll(b); ++i)
#define fo(i,a) forn(i,0,ll(a))
#define rforn(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define ro(i,a) rforn(i,0,a)
#define trav(a,x) for (auto& a: x)

#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define rsz resize
#define ins insert

#define mp make_pair
#define pb push_back
#define eb emplace_back
#define f first
#define s second

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef CREED
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

const ll INF = 1e18;

ll mod = 1000000007;
inline ll fast_expo(ll base,ll power,ll modulo=mod){
    base%=modulo;
    if (base<0) base+=modulo;
    ll x=base,cnt=power,ans=1;
    while(cnt){
        if (cnt&1) ans=(ans*x)%modulo;
        x=(x*x)%modulo;
        cnt>>=1;
    }
    return ans;
}

ll takemod(ll a, ll mo){
	a %= mo;
	if(a < 0) a+=mo;
	return a;
}

// if mod is prime
ll modinv(ll a, ll mo){
	return takemod(fast_expo(takemod(a,mo), mo-2, mo), mo);
}

//=========================CODE STARTS HERE=============================//


int main() {
    fast_cin();
    debug("Rupanshu");
    str arr, arr2;
    cin >> arr >> arr2;
    ll n = arr.length();
    ll m = arr2.length();
    ll dp[n + 1][m + 1];
    
    memset(dp, 0, sizeof(dp));
    
    for (int i = 1; i <= n; ++i) {
	for (int j = 1; j <= m; ++j) {
	    dp[i][j] = max(dp[i - 1][j], max(dp[i][j - 1], dp[i - 1][j - 1] + (arr2[j - 1] == arr[i - 1])));
	}
    }
    
    
    ll count = dp[n][m];
    ll ptr1 = n, ptr2 = m;
    str ans = "";
    while (count > 0 && ptr1 > 0 && ptr2 > 0) {
	if (dp[ptr1][ptr2] == dp[ptr1 - 1][ptr2 - 1] + (arr2[ptr2 - 1] == arr[ptr1 - 1])) {
	    if ((arr2[ptr2 - 1] == arr[ptr1 - 1]))
		ans += arr[ptr1 - 1];
	    ptr1--;
	    ptr2--;
	}else if (dp[ptr1][ptr2] == dp[ptr1 - 1][ptr2]) {
	    ptr1--;
	}else {
	    ptr2--;
	}
    }
    
    reverse(all(ans));
    
    cout << ans;
	
    return 0; 
}


Measured memory_bytes: 70784