import of keras and tensorflow seems to break pycharm

I'm facing a weird issue.

I'm working in Pycharm IDE and I want to use keras with tensorflow backend. When I try to import keras or tensorflow pycharm process finished with exit code -1073741819 (0xC0000005).

For example

import tensorflow as tf 
n_input = 2
print (n_input)

returns message described above without printing anything. If i comment the tf import it works.

Keras and tensorflow are correctly installed under the python interpreter of my choice.

I'm on windows machine, Python 3.6.8

Thanks