Given $n$ string $S_i$. Count the number of pairs $i \neq j$ that $S_iS_j$ is a palindrome. $(i,j)$ is different from $(j,i)$.
### Input
- The first line contains an integer $n$.
- The next $n$ lines, each line contains a string $S_i$, each string contains only lowercase letters.
### Output
- Print the number of pairs.
### Constraints
- $1 \le n \le 10^5$.
- $1 \le \sum{|S_i|} \le 10^6$
### Example
Input:
```
3
a
b
ab
```
Output:
```
2
```