Challenge: Generate a 64 in the display (RPN)

[Hlib]

Russian RPN "mk-61" calculator:
1) | pi | x^2 | sign | LSTx | - | INT | x^2 |
(7 steps/13 keystrokes)
* suitable for all classic RPN machines.
2) | pi | x^2 | STO_1 | RCL(i)_1 | RCL_1 | x^2 |
(6 steps/13 keystrokes)
** RCL(i)_1 in "mk" works as INT(R1-1)➝R1 .
3) | CLRx | AND | x^2 |
EDIT: The terms of the challenge stated:

Quote:You may not use any of the digit keys 0 - 9

The [CLRx] command is almost equivalent to using the [0] key.
Therefore, it is better not to use it either. Now my conscience will be at ease:
3) | ENTER↑ | XOR | x^2 |
EDIT_END
(3 steps/5 keystrokes)
*** for "mk" only.