Count Distinct Swappable Digit Pairs

For each i<j, the pair is valid if the decimal representation of numbers[j] can become numbers[i] with at most one swap (swapping one pair of positions); no swap is also allowed. Only numbers with the same number of digits are counted. Find the number of pairs. A swap must not create a leading zero.

输入格式

The first line contains n (1..100000), and the second line contains n integers (0..10^9) in ordinary decimal representation.

输出格式

Output the number of valid pairs; the result may exceed 32 bits.

样例 1

输入：

4
12 21 12 123

输出：

3

样例 2

输入：

2
7 7

输出：

1

样例 3

输入：

4
1 10 100 1000

输出：

0