package algs63; // section 6.3
import stdlib.*;
/* ***********************************************************************
 *  Compilation:  javac LRS.java
 *  Execution:    java LRS < file.txt
 *  Dependencies: StdIn.java SuffixArray.java
 *  Data files:   http://algs4.cs.princeton.edu/63suffix/tinyTale.txt
 *                http://algs4.cs.princeton.edu/63suffix/mobydick.txt
 *
 *  Reads a text string from stdin, replaces all consecutive blocks of
 *  whitespace with a single space, and then computes the longest
 *  repeated substring in that text using a suffix array.
 *
 *  % java LRS < tinyTale.txt
 *  'st of times it was the '
 *
 *  % java LRS < mobydick.txt
 *  ',- Such a funny, sporty, gamy, jesty, joky, hoky-poky lad, is the Ocean, oh! Th'
 *
 *  % java LRS
 *  aaaaaaaaa
 *  'aaaaaaaa'
 *
 *  % java LRS
 *  abcdefg
 *  ''
 *
 *************************************************************************/


public class LRS {

	public static void main(String[] args) {
		String text = StdIn.readAll().replaceAll("\\s+", " ");
		SuffixArray sa = new SuffixArray(text);

		int N = sa.length();

		String lrs = "";
		for (int i = 1; i < N; i++) {
			int length = sa.lcp(i);
			if (length > lrs.length())
				lrs = sa.select(i).substring(0, length);
		}

		StdOut.println("'" + lrs + "'");
	}
}