1. (20 points) Consider demand paging. You are given the following reference string, page replacement policy and the number of frames available. Calculate the number of page faults in each case. To answer the question, write down the # of page fault, and also copy the referencestring and circle all references that causes a page fault. Notice that we assume no pages exists in the frames in the beginning, thus, the initial pages being loaded into the frames should count as page faults. Another way to look at it is to assume page faults = number of times a page need to be loaded into main memory (assume nothing is there in the first place).