CH8 Biologist

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

/*
 * Tuenti Contest
 * Challenge 8 - Biologist
 * Author: Pedro Antonio Pardal Jimena
 * Email: pardal@alu.uma.es
 */

public class Biologist
{
    private static String longestCommonSubstring( String s1, String s2 )
    {
        int start = 0;
        int max = 0;
        for ( int i = 0; i < s1.length(); i++ )
        {
            for ( int j = 0; j < s2.length(); j++ )
            {
                int x = 0;
                while ( s1.charAt(i + x) == s2.charAt(j + x) )
                {
                    x++;
                    if ( (i + x >= s1.length()) || (j + x >= s2.length()) )
                        break;
                }

                if ( x > max )
                {
                    max = x;
                    start = i;
                }
            }
        }

        return s1.substring( start, start + max );
    }

    private static String parseInput( String linea )
    {
        StringTokenizer st = new StringTokenizer( linea, " " );

        String s1 = st.nextToken();
        String s2 = st.nextToken();

        return longestCommonSubstring( s1, s2 );
    }

    public static void main( String[] args ) throws IOException
    {
        BufferedReader reader = new BufferedReader( new InputStreamReader( System.in ) );

        while ( reader.ready() )
        {
            String linea = reader.readLine();
            String result = parseInput( linea );

            System.out.println( result );
        }
    }
}