How do I install python, pip again on Mac?

Question

I tried to change the default python 2.7 to python 3.6 in MacBook Air by the command nano ~/.bash_profile and changed the external path for python..but then i accidentally deleted the inbuilt python folder too.. so now i can't run any python code on terminal.. I also tried installing it again but then it shows pip command not found.. Tried installing pip too but it didn't work..
What should I do to install python again?