题号：NC214395
时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
Special Judge, 64bit IO Format: %lld
题目描述
Bobo has n strings s1, ... , sn, and he would like to find the number of pairs i < j where si + sj = sj + si.
Note that a + b means the concatenation of the string a and b, i.e., writing the string a first, and the string b second.
输入描述:
The input consists of several test cases terminated by end-of-file.
The first line of each test case contains an integer n. The i-th of the following n lines contains a string si.
· 1 ≤ n ≤ 105
· |si| ≤ 106, si contains only lower case characters.
· The sum of strings does not exceed 5×106
输出描述:
For each test case, print an integer which denotes the result.
示例1
输入
复制
2
a
ab
2
ab
ab
3
a
aa
aaa