#757. Pairs with difference d
Count the pairs with i < j and |a[i] - a[j]| = d.
### Input
The first line has n, the second line has n integers separated by spaces. The third line has d.
### Output
A number.
Examples
Input
15 10 2 1 3 2 4 3 0 4 10 9 2 2 10 4 5
Output
3
Input
10 3 3 7 4 10 8 2 10 5 9 2
Output
7
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.