#620. Number of different values
You are given a list of integers. **Number of different values**. If there is no second value, print `None`. If the answer has several numbers, separate them with spaces.
### Input
The first line has n, the second line has n integers separated by spaces.
### Output
The answer.
Examples
Input
7 0 -18 17 -14 20 14 -16
Output
7
Input
6 1 -7 -2 3 1 12
Output
5
💡 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.