using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Runtime.CompilerServices;
using ll=System.Int64;

public class Contest
{
	static void Swap1<T>(ref T a, ref T b) { T t = a; a = b; b = t; }
	static void Swap2<T>(ref T a, ref T b) where T : IComparable { if (a.CompareTo(b)==1) Swap1(ref a, ref b); }  // b の方が小さければ交換
	static bool Chmin<T>(ref T a, T b) where T : IComparable { if (a.CompareTo(b)== 1) { a = b; return true; } return false; }  // b の方が小さければ a を更新
	static bool Chmax<T>(ref T a, T b) where T : IComparable { if (a.CompareTo(b)==-1) { a = b; return true; } return false; }  // b の方が大きければ a を更新
	static T[][] InitMat<T>(long len1, long len2, T val){ T[][] m = new T[len1][]; for (int i = 0; i < m.Length; i++) m[i] = Enumerable.Repeat(val, (int)len2).ToArray(); return m; }
	static T[][][] InitMat<T>(long len1, long len2, long len3, T val){ T[][][] m = new T[len1][][]; for (int i = 0; i < m.Length; i++) m[i] = InitMat(len2,len3,val); return m; }
	public const long MOD1 = 1000000007; // 10^9+7
	public const double EPS1 = 1e-8;

	public static void Main() {
		Solve_F();
 	}

	public static void Solve_A() {
		long  n,k;
		MyIO.ReadMulti(out n, out k);
		ll[] h;
		MyIO.ReadArray(out h);

		if(n<k) k=n;
		ll[] dp = new ll[n+1];
		dp[0] = 0;
		for (int i = 1; i <= k; i++)
		{
			dp[i] = Math.Abs(h[0]-h[i]);
		}
		for (int i = (int)k+1; i < n; i++)
		{
			ll min = ll.MaxValue;
			for (int j = 1; j <= k; j++)
			{
				Chmin(ref min, dp[i-j] + Math.Abs(h[i-j]-h[i]));
			}
			dp[i] = min;
		}


		long ans = dp[n-1];


		MyIO.WriteMulti(ans);
	}
	public static void Solve_B() {
		long  n,k;
		MyIO.ReadMulti(out n, out k);
		ll[] h;
		MyIO.ReadArray(out h);

		if(n<=k) k=n-1;
		ll[] dp = new ll[n+1];
		dp[0] = 0;
		for (int i = 1; i <= k; i++)
		{
			dp[i] = Math.Abs(h[0]-h[i]);
		}
		for (int i = (int)k+1; i < n; i++)
		{
			ll min = ll.MaxValue;
			for (int j = 1; j <= k; j++)
			{
				Chmin(ref min, dp[i-j] + Math.Abs(h[i-j]-h[i]));
			}
			dp[i] = min;
		}


		long ans = dp[n-1];


		MyIO.WriteMulti(ans);
	}
	public static void Solve_C() {
		long  n;
		MyIO.ReadMulti(out n);
		VT<ll,ll,ll>[] abcl;
		MyIO.ReadLines(n, out abcl);

		ll[][] dp = InitMat(n+1,3,0L);
		for (int i = 1; i <= n; i++)
		{
			dp[i][0] = Math.Max(dp[i-1][1],dp[i-1][2])+abcl[i-1].Item1;
			dp[i][1] = Math.Max(dp[i-1][2],dp[i-1][0])+abcl[i-1].Item2;
			dp[i][2] = Math.Max(dp[i-1][0],dp[i-1][1])+abcl[i-1].Item3;
		}


		long ans = dp[n].Max();


		MyIO.WriteMulti(ans);
	}
	public static void Solve_D() {
		long  n, w;
		MyIO.ReadMulti(out n, out w);
		VT<ll,ll>[] wvl;
		MyIO.ReadLines(n, out wvl);

		ll[][] dp = InitMat(n+1,100001,ll.MaxValue);
		dp[0][0] = 0;
		for (int i = 0; i < n; i++)
		{
			for (int j = 100000; 0<=j; j--)
			{
				dp[i+1][j] = dp[i][j];
				Chmin(ref dp[i+1][j],(0<=j-wvl[i].Item2)?(dp[i][j-wvl[i].Item2]+wvl[i].Item1):ll.MaxValue);
//				Chmin(ref dp[i+1][j],(j<100000)?(dp[i+1][j+1]):ll.MaxValue);
			}

		}

		long ans = -1;
		for (int i = 100000; 0<=i; i--)
		{
			if(dp[n][i]<=w) {
				ans = i;
				break;
			}
		}

		MyIO.WriteMulti(ans);
	}
	public static void Solve_E() {
		long  n, w;
		MyIO.ReadMulti(out n, out w);
		VT<ll,ll>[] wvl;
		MyIO.ReadLines(n, out wvl);

		ll[][] dp = InitMat(n+1,100001,100000000000);
		dp[0][0] = 0;
		for (int i = 0; i < n; i++)
		{
			for (int j = 100000; 0<=j; j--)
			{
				dp[i+1][j] = dp[i][j];
				Chmin(ref dp[i+1][j],(0<=j-wvl[i].Item2)?(dp[i][j-wvl[i].Item2]+wvl[i].Item1):100000000000);
			}

		}

		long ans = -1;
		for (int i = 100000; 0<=i; i--)
		{
			if(dp[n][i]<=w) {
				ans = i;
				break;
			}
		}

		MyIO.WriteMulti(ans);
	}
	public static void Solve_F() {
		string s,t;
		MyIO.ReadMulti(out s);
		MyIO.ReadMulti(out t);



		MyIO.WriteMulti(LCS(s,t));
	}





	public static string LCS(string s1, string s2)
	{
		int[,] c = new int[s1.Length + 1, s2.Length + 1];
		for (int i = 1; i <= s1.Length; i++){
			for (int j = 1; j <= s2.Length; j++)
			{
				if (s1[i - 1] == s2[j - 1])
					c[i, j] = c[i - 1, j - 1] + 1;
				else                   
					c[i, j] = c[i - 1, j] > c[i, j - 1]? c[i - 1, j] : c[i, j - 1];
			}
		}
		return BackTrack(c, s1, s2, s1.Length, s2.Length);
	}
	private static string BackTrack(int[,] c, string s1, string s2, int i, int j)
	{
		if (i == 0 || j == 0) 
			return "";
		else if (s1[i - 1] == s2[j - 1])
			return BackTrack(c, s1, s2, i - 1, j - 1) + s1[i - 1];
		else if (c[i, j - 1] > c[i - 1, j])
			return BackTrack(c, s1, s2, i, j - 1);
		else
			return BackTrack(c, s1, s2, i - 1, j);
	}









}




















#region MyIO

public struct VT<T, U>
{
	public T Item1; public U Item2;
    public VT(T a, U b) { Item1 = a; Item2 = b; }
}
public struct VT<T, U, V>
{
	public T Item1; public U Item2; public V Item3;
    public VT(T a, U b, V c) { Item1 = a; Item2 = b; Item3 = c; }
}
public struct VT<T, U, V, W>
{
	public T Item1; public U Item2; public V Item3; public W Item4;
    public VT(T a, U b, V c, W d) { Item1 = a; Item2 = b; Item3 = c; Item4 = d; }
}

public class Printer : System.IO.StreamWriter
{
	public override IFormatProvider FormatProvider { get { return System.Globalization.CultureInfo.InvariantCulture; } }
	public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
	public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { }
}
public static class MyIO
{
	private static char[] splitter = new char[] {' '};
	private static bool eq<T, U>() => typeof(T).Equals(typeof(U));
	private static T ct<T, U>(U a) => (T)Convert.ChangeType(a, typeof(T));
	private static T cv<T>(string s) =>
		eq<T, int>()    ? ct<T, int>(int.Parse(s))
	  : eq<T, long>()   ? ct<T, long>(long.Parse(s))
	  : eq<T, double>() ? ct<T, double>(double.Parse(s, System.Globalization.CultureInfo.InvariantCulture))
	  : eq<T, char>()   ? ct<T, char>(s[0])
						: ct<T, string>(s);
			
	public static string[] ReadMulti<T>(out T a) {
		var ar = Console.ReadLine().Split(splitter, StringSplitOptions.RemoveEmptyEntries); 
		a = cv<T>(ar[0]);
		return ar;
	}
	public static string[] ReadMulti<T, U>(out T a, out U b) {
		var ar = ReadMulti<T>(out a); 
        b = cv<U>(ar[1]);
		return ar;
	}
	public static string[] ReadMulti<T, U, V>(out T a, out U b, out V c) {
		var ar = ReadMulti<T, U>(out a, out b); 
        c = cv<V>(ar[2]);
		return ar;
	}
	public static string[] ReadMulti<T, U, V, W>(out T a, out U b, out V c, out W d) {
		var ar = ReadMulti<T, U, V>(out a, out b, out c); 
        d = cv<W>(ar[3]);
		return ar;
	}
	public static string[] ReadMulti<T, U, V, W, X>(out T a, out U b, out V c, out W d, out X e) {
		var ar = ReadMulti<T, U, V, W>(out a, out b, out c, out d); 
        e = cv<X>(ar[4]);
		return ar;
	}
	public static string[] ReadMulti<T, U, V, W, X, Y>(out T a, out U b, out V c, out W d, out X e, out Y f) {
		var ar = ReadMulti<T, U, V, W, X>(out a, out b, out c, out d, out e); 
        f = cv<Y>(ar[5]);
		return ar;
	}
	public static string[] ReadArray<T>(out T[] a) {		
		var ar = Console.ReadLine().Split(splitter, StringSplitOptions.RemoveEmptyEntries);
		a = ar.Select(cv<T>).ToArray();
		return ar;
	}		
	public static string[][] ReadLines<T>(long n, out T[] a) {
		a = new T[n];
		string[][] arr = new string[n][];
		for(int i=0; i<n; i++) arr[i] = ReadMulti(out a[i]);
		return arr;
	}
	public static string[][] ReadLines<T, U>(long n, out VT<T, U>[] a) {
		a = new VT<T, U>[n];
		string[][] arr = new string[n][];
		for(int i=0; i<n; i++) {
			T o; U p;
			arr[i] = ReadMulti(out o, out p);
			a[i] = new VT<T, U>(o, p);
		}
		return arr;
	}
	public static string[][] ReadLines<T, U, V>(long n, out VT<T, U, V>[] a) {
		a = new VT<T, U, V>[n];
		string[][] arr = new string[n][];
		for(int i=0; i<n; i++) {
			T o; U p; V q;
			arr[i] = ReadMulti(out o, out p, out q);
			a[i] = new VT<T, U, V>(o, p, q);
		}
		return arr;
	}
	public static string[][] ReadLines<T, U, V, W>(long n, out VT<T, U, V, W>[] a) {
		a = new VT<T, U, V, W>[n];
		string[][] arr = new string[n][];
		for(int i=0; i<n; i++) {
			T o; U p; V q; W r;
			arr[i] = ReadMulti(out o, out p, out q, out r);
			a[i] = new VT<T, U, V, W>(o, p, q, r);
		}
		return arr;
	}
	public static string[][] ReadMatrix<T>(long n, out T[][] a) {
		a = new T[n][];
		string[][] arr = new string[n][];
		for(int i=0; i<n; i++) arr[i] = ReadArray(out a[i]);
		return arr;
	}

	private static void wwp(Action act){
		var sw = new Printer(Console.OpenStandardOutput()){AutoFlush = false};
		Console.SetOut(sw);
		act();
		Console.Out.Flush();
		sw.AutoFlush = true;
		Console.SetOut(sw);
	}
	private static string wfm(Type t) =>t.Equals(typeof(double)) ? "{0:F10}" : "{0}";
	public static void WriteMulti(params object[] a) {
		wwp(()=>{
			for(int i=0;i<a.Length;i++) {
				string fs = wfm(a[i].GetType()) + ((i<a.Length-1) ? " " : Environment.NewLine);
				Console.Write(fs, a[i]);
			}
		});
	}
	public static void WriteArray<T>(T[] a) {
		wwp(()=>{
			string fs = wfm(typeof(T));
			string fs1 = fs + " ";
			string fs2 = fs + Environment.NewLine;
			for(int i=0;i<a.Length;i++) Console.Write( ((i<a.Length-1) ? fs1 : fs2), a[i]);
		});
	}
	public static void WriteLines<T>(T[] a) {
		wwp(()=>{
			string fs = wfm(typeof(T)) + Environment.NewLine;
			foreach(T x in a) Console.Write(fs, x);
		});
	}


}

#endregion



Measured memory_bytes: 50360