A8326. Password

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.
Asterix、Obelix 和他们的临时伙伴 Suffix 和 Prefix 终于找到了和谐神殿。然而，神殿的大门紧紧地锁着，就连欧比也无法打开。

过了一会儿，他们在寺庙大门下面的一块石头上发现了一个字符串 s 。亚力认为这是打开神庙的密码，于是大声念了出来。然而，什么也没发生。然后，亚力认为密码是 s 的子串 t 。

前缀认为，子串 t 是字符串 s 的开头；后缀认为，子串 t 应该是字符串 s 的结尾；而后缀认为， t 应该位于字符串 s 的某处，也就是说， t 既不是它的开头，也不是它的结尾。

为了让所有同伴满意，Asterix 选择了 t 这个子串。此外，在所有可接受的变体中，Asterix 选择了最长的一个(因为 Asterix 喜欢长串)。当 Asterix 大声读出 t 子串时，神殿的大门打开了。

你知道字符串 s 。找出 t 的子串，或者确定这样的子串并不存在，上面所写的只是一个美丽的传说。

You are given the string $s$ whose length can vary from $1$ to $10^{6}$ (inclusive), consisting of small Latin letters.
输入
我们会给你一个字符串 s ，其长度从 1 到 106 (含)不等，由小的拉丁字母组成。

Print the string $t$ . If a suitable $t$ string does not exist, then print "Just a legend" without the quotes.
输出
打印字符串 t 。如果不存在合适的 t 字符串，则打印"只是一个图例"，去掉引号。