只要努力飞翔，即使再弱小的蝴蝶也可以飞的很高
1524 - [POI2006]Pal
给出n个回文串s1, s2, …, sn 求如下二元组(i, j)的个数 si + sj 仍然是回文串 规模 输入串总长不超过2M bytes
Input
The first line of input file contains the number of strings n. The following n lines describe each string: The i+1-th line contains the length of the i-th string li, then a single space and a string of li small letters of English alphabet. You can assume that the total length of all strings will not exceed 2,000,000. Two strings in different line may be the same.
Output
Print out only one integer, the number of palindromes
Examples
Input
6 2 aa 3 aba 3 aaa 6 abaaba 5 aaaaa 4 abba
Output
14