plz help

Q No. 3: Consider the following page reference string: (8 Marks) 1, 2, 3, 4, 2, 1, 5, 6, 2, 1, 2, 3, 7, 6, 3, 2, 1, 2, 3,6 Indicate the page faults and calculate the total number of page faults for FIFO, Optimal and LRU algorithms also discuss the difference between page faults of each algorithm. Assume there are 7 frames are empty