Password

题面翻译

Asterix，Obelix 和他们的临时伙伴 Suffix、Prefix 已经最终找到了和谐寺。然而和谐寺大门紧闭，就连 Obelix 的运气也没好到能打开它。

不久他们发现了一个字符串 $S\ (1\leqslant\vert S\vert\leqslant1000000)$，刻在和谐寺大门下面的岩石上。Asterix 猜想那一定是打开寺庙大门的密码，于是就大声将字符串朗读了出来，然而并没有什么事发生。于是 Asterix 又猜想密码一定是字符串 $S$ 的子串 $T$。

Prefix 认为 $T$ 是 $S$ 的前缀，Suffix 认为 $T$ 是 $S$ 的后缀，Obelix 却认为 $T$ 应该是 $S$ 中的某一部分，也就是说，$T$ 既不是 $S$ 的前缀，也不是 $S$ 的后缀。

Asterix 选择子串 $T$ 来满足所有伙伴们的想法。同时，在所有可以被接受的子串变形中，Asterix 选择了最长的一个。当 Asterix 大声读出子串 $T$ 时，寺庙的大门开了。（也就是说，你需要找到既是 $S$ 的前缀又是 $S$ 的后缀同时又在 $S$ 中间出现过的最长子串）

现在给你字符串 $S$，你需要找到满足上述要求的子串 $T$。

输入格式

一行一个只包含小写字母的字符串 $S$。

输出格式

输出子串 $T$，如果 $T$ 不存在，输出 Just a legend。

题目描述

Asterix, Obelix and their temporary buddies Suffix and Prefix has finally found the Harmony temple. However, its doors were firmly locked and even Obelix had no luck opening them.

A little later they found a string $s$ , carved on a rock below the temple's gates. Asterix supposed that that's the password that opens the temple and read the string aloud. However, nothing happened. Then Asterix supposed that a password is some substring $t$ of the string $s$ .

Prefix supposed that the substring $t$ is the beginning of the string $s$ ; Suffix supposed that the substring $t$ should be the end of the string $s$ ; and Obelix supposed that $t$ should be located somewhere inside the string $s$ , that is, $t$ is neither its beginning, nor its end.

Asterix chose the substring $t$ so as to please all his companions. Besides, from all acceptable variants Asterix chose the longest one (as Asterix loves long strings). When Asterix read the substring $t$ aloud, the temple doors opened.

You know the string $s$ . Find the substring $t$ or determine that such substring does not exist and all that's been written above is just a nice legend.

输入格式

You are given the string $s$ whose length can vary from $1$ to $10^{6}$ (inclusive), consisting of small Latin letters.

输出格式

Print the string $t$ . If a suitable $t$ string does not exist, then print "Just a legend" without the quotes.

样例 #1

样例输入 #1

fixprefixsuffix

样例输出 #1

fix

样例 #2

样例输入 #2

abcdabc

样例输出 #2

Just a legend