a = 2

b = 3

c = 4

c = 5

c = 6

c = 7

c = 8

c = 9

c = 10

c = 11

b = 4

c = 5

c = 6

c = 7

b = 5

a = 3

Finally, the good solutions are:

a 2 2 2 2 2 2
b 3 3 3 3 4 4
c 7 8 9 10 5 6
d 42 24 18 15 20 12