Given the following order of numbers:

1 2 3 4 5 6 7 8 9 10 11 12

Insert either a plus sign or a minus sign or neither between the digits to make a sum that adds up to 666.

What is the the fewest amount of + and - required to do this?

Here is an example of a valid expression but with the wrong answer, ie it doesn't add up to 666.

12-3+456-7-8-9+1011-12 = 1440