This is min-cost perfect matching, but I do not understand.

Question 3. Hungarian algorithm for min-cost perfect matching (20 marks) Solve the instance of the min-cost perfect matching problem depicted below using the Hun- garian algorithm (the algorithm presented in the lectures). For each iteration of the algo- rithm, draw the equality subgraph, label the vertices with their potentials, mark the perfect matching or decient subset, and then write the increment in potential, if any. Indicate which edges you considered in calculating the increment