Consider the following page$-$reference string:

$1,2,3,4,2,1,5,6,2,1,2,3,7,6,3,2,1,2,3,6,2,1$

How many page faults would occur for the following replacement algorithms, when the number of frames allocated are three and four, respectively? Remember that all frames are initially empty, so your unique pages will all cost one fault each.

$$ LRU replacement

$$ FIFO replacement

$$ MIN, Optimal replacement

make sure it is how its supposed to be and correct and draw tables for each replacement