CMU 1st/2nd Major Choice: Does it matter?

I am interested in attending CMU for mathematics and computer science (theory focused). I am unsure what to put down as my first and second major of interest. Would putting SCS as my first-choice major make my chances of getting accepted into MCS lesser in any way? I would be ecstatic to be in the SCS major (but my SAT scores are not too hot) and I would also be very happy majoring in math and just taking courses in CS theory (possibly picking up a minor or even double major in CS).

So should I just put SCS as my first choice? Thoughts?

getting into SCS is significantly harder, so I would pick it first choice. How good are your SAT math score?

700 on the new Exam @idkName
670 SAT II

My subject test was pretty poor because I didn’t know subject tests were required for a lot of college applications until this summer and I did not study (but I am retaking it and am sure it will improve at least some)

edit
I forgot CMU won’t accept my retake as it is likely too late for those scores to matter

removed due to edit