how read from 50 or maybe more inputs(50 pins)

I want to read from my arduino from 50 or maybe more pins. I have understand that i can do this with a Shift Register(ICs). I what's the bigest shift register i can find, and if this is the best practice to do it.

Thanks.

Hi,

Arduino MEGA has 54 I/O pins (and 16 Analog that can be used as digital). What other pins do you need to use in your application?

Look at 74HC165 shift register and "ShiftIn" command if you want to do that.

what's the bigest shift register i can find,

It is 8 bits. what you do when you want more inputs is to chain them together, as many as you like. This is done simply by putting the output of one shift register to the input of another.