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Time Limit: 5 s Memory Limit: 4 MB Total points: 10

#227. 回文 [B]

Statistics

请注意本题中极小的内存限制。

阿波罗登月火箭上的计算机拥有 71 KB 的内存。在本题中,你将拥有更多的内存,即 4 MB,而你的任务也更简单:你需要检查输入的一个单词是否为回文。回文是指从左向右读和从右向左读都相同的单词,例如 kajakinni

为了增加难度,在某些测试用例中,单词的长度在读取前是未知的。

输入格式

输入的第一行包含一个整数 $n$。在某些测试组中,这是一个正整数,表示第二行给出的单词长度。在其他测试组中,$n = 0$,这意味着你需要从输入中读取单词,且事先不知道其长度。

第二行包含待检查的单词,由小写英文字母组成。该单词非空,且长度不超过 $20\,000\,000$ 个字符。

你可以假设在每一组测试中,要么所有测试用例都有 $n > 0$,要么所有测试用例都有 $n = 0$。

输出格式

输出一行,包含 TAKNIE,取决于给定的单词是否为回文。

样例

输入 1

5
kajak

输出 1

TAK

输入 2

0
kanu

输出 2

NIE

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