Term for 'Do not worry about what you cannot control'

This quote which became like a proverb might help:

We can't direct the wind but we can adjust the sails.

It is attributed to several authors, like for example, Thomas S. Monson.

It is not easy to find official definitions of this, but this site says

In this quote the Thomas S. Monson is trying to say is that most of the times we cannot control the situations but we can control our response to those situation which will decide our course in life.