#856. Different substrings of length 2
You get a string. How many different substrings (characters next to each other) of length 2 does it have? Use a set.
### Input
One line (length ≥ 2).
### Output
A number.
Examples
Input
baabbbaaababba
Output
4
Input
ababbbaabbbbb
Output
4
💡 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.