Multiple nested functions

I'm trying to create a spreadsheet that will tell me my fantasy football score when I enter in required information. I'm stuck on a nested if function. I've attached the file and below is the formula that I'm trying to use in cell J13.
If the defense allows 0 points I want the formula to return 10 points
if the defense allows 2-6 points I want the formula to return 7 points
7-13 points allowed - return 4 points
14-17 points allowed - return 1 points
18-21 points allowed - return 0 points
22-27 points allowed - return -1 points
28-34 points allowed - return -4 points
35-45 points allowed - return -7 points
46 and above points allowed - return -10 points

=IF(B13=0,10,IF(AND(B13>=2,B13<=6),7,IF(AND(B13>=7,B13<=13),4,IF(AND(B13>=14,B13<=17),1,IF(AND(B13>=18,B13<=21),0,IF(AND(B13>=22,B13<=27),-1,IF(AND(B13>=28,B13<=34),-4,=IF(AND(B13>=35,B13<=45),-7,-10))))))))