Read the passage below and solve the questions based on it.
Pankaj has six friends, and during a certain vacation he met them at several dinners. He found that he dined with all six friends exactly one day; with every five of them of 2 days; with every four of them of 3 days; with every three of them of 4 days; with every two of them of 5 days. Further, every friend was present at 8 dinners and every friend was absent at 8 dinners.
When Pankaj had dinner with every three of them of 4 days and every two of them of 5 days, what was the minimum number of friends who had dinner twice in these 9 days?