#P1093. String Commutativity

    ID: 94 远端评测题 1000ms 128MiB 尝试: 0 已通过: 0 难度: (无) 上传者: 标签>湖南省第十六届大学生计算机程序设计竞赛(HNCPC2020)

String Commutativity

Description

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.

Input

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| ≤ 106si contains only lower case characters.
  • The sum of strings does not exceed 5 × 106.

Output

For each test case, print an integer which denotes the result.

2
a
ab
2
ab
ab
3
a
aa
aaa
0
1
3