please explain step by step

1. Present the performance of Greedy-Set-Cover algorithm on the instance: the set S = {1, 2, ...,26} and the family of subsets F = {S; = {2, 4, 8, 13, 17, 20, 23}, S2 = {7, 12, 14, 16, 18, 25}, S3 = {7,8, 18, 22, 25}, S4 = {1, 9, 10, 11, 19, 24}, S5 = {1,6, 15, 19, 22}, S6 = {2, 7, 10, 13, 21, 24}, S7 = {1, 2, 8, 13, 21, 22}, S8 = {4, 12, 15, 17, 20, 23, 25, 26}, Sg = {3, 5, 11, 13, 14, 17, 18, 24, 25}}