Hi, @naneki
Can you post a link to data/specs of the L293D board that you have please?
Have you tried one of the Example codes first to see if you are connected to the motor controller?
You appear to have no void setup() section in your code.
You need to develop your code in stages, not one big code at once.
Can I suggest you try and control ONE motor, to prove your hardware.
THEN 2 motors, then then 4.
Then write code to test your joysticks with the IDE serial monitor.
When you have that working properly, combine the two.
Thanks.. Tom... 
