+(addition), -(subtraction), /(division), x(multiplication), =(equals)

It is a simple calculator that can do one binary operation at a time.

The only functional digit is 7.

How is it possible for 34 to appear in the readout in the fewest number of keystrokes?

__Notes__:

1. Performing as many operations as possible is allowed.

2. The digit 7 may be reused, that is expressions like 777x77 or, 7777+7 in a given operation is allowed.