Smiley Faces :)

You will be given a string of characters containing only the three characters: ( ) :

Create a function that returns a number based on the number of sad and smiley faces there are.

• The happy faces :) and (: are worth 1.
• The sad faces :( and ): are worth -1.

Worked Example

happiness_number(":):(") ➞ -1
# The first 2 characters are :)        +1      Total: 1
# 2nd and 3rd characters are ):     -1      Total: 0
# 3rd and 4th characters are :(      -1      Total: -1

Examples

happiness_number(":):(") ➞ -1

happiness_number("(:)") ➞ 2

happiness_number("::::") ➞ 0

Notes

All test cases will be valid.