#779. Pairs with a sum divisible by 3
Count the pairs with i < j where a[i] + a[j] is divisible by 3.
### Input
The first line has n, the second line has n integers separated by spaces.
### Output
A number.
Examples
Input
7 12 28 31 40 30 10 21
Output
3
Input
11 32 31 23 35 42 32 24 46 24 24 9
Output
18
💡 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.