Letters of Rec advice?!

I believe my strongest recs will come from my previous math and AP Chem teacher, however I know schools usually want a letter from a STEM subject and humanities.
For my top two reaches (Brown and Dartmouth), would submitting a letter from a math and science teacher hurt me? (I plan on majoring in something related to public health, econ, or CS I think…)
Or, should I do my AP Chem teacher and my AP Chinese teacher?