Sean has a faulty calculator such that:

The only keys that do anything on his calculator, with the function they actually perform, are:

- Subtact 1 from the display.
+ Add 2 to the display.
x Cube the display value.
M+ Add the display value to the memory.
M- Subtract the display value from the memory.
MC Clear the memory (but not the display).
MR Recall the memory, replacing the display value.

The display and memory are both zero before you start.

Determine the minimum number of key presses that Sean needs to perform on his calculator to obtain the number 2004.