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

int main(){
	string a;
	string b;
	cin>>a>>b;
	int n=a.size();
	int m=b.size();
	int dp[n+1][m+1];
	for(int i=0;i<=n;i++)
	{
		for(int j=0;j<=m;j++)
		{
			if(!i||!j)dp[i][j]=0;
			else if(a[i-1]==b[j-1])dp[i][j]=dp[i-1][j-1]+1;
			else dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
		}
	}
	
	string ans="";
	int i = n, j = m; 
    while (i > 0 && j > 0) 
    {
	    if (a[i-1] == b[j-1]) 
	    { 
		    ans=a[i-1]+ans;
		    i--; j--;   
	    }
	    else if (dp[i-1][j] > dp[i][j-1])i--; 
	    else j--; 
    }
	cout<<ans;
	return 0;
}
