UCLA Pre Math/Econ Transfer Summer Session

I have been admitted with Pre Math/Econ major, but I have not taken the following pre-major:
Math 33B(Differential Equations), Math 61(Introduction to Discrete Structures), PIC 10A(Introduction to Programming), and Econ 11(Microeconomic Theory).
Most of them are not articulated in my community college.

Deciding to attend the summer sessions in UCLA, I hope to receive some advice from you guys.

  1. Should I take Math 61 or PIC 10A in Summer Session A?
  2. Econ 11 or Math 33B in Session C?

Notice that PIC 10A is a 8 weeks course, so there is a time conflict between PIC 10A and Math 33B. If I choose Math 33B, there is no way for me to do PIC 10A.

Is it difficult for me to graduate within 2 years?
Could I take any upper division course before finishing all pre-major?