#P1093. String Commutativity
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| ≤ 106, si 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