* group 0
students: 7 12 1
common interests between 1 and 2: 1
common interests between 1 and 3: 1
common interests between 2 and 3: 0
total= 2
* group 1
students: 13 2 10
common interests between 1 and 2: 0
common interests between 1 and 3: 1
common interests between 2 and 3: 0
total= 1
* group 2
students: 3 4 14
common interests between 1 and 2: 1
common interests between 1 and 3: 1
common interests between 2 and 3: 0
total= 2
* group 3
students: 8 5 11
common interests between 1 and 2: 0
common interests between 1 and 3: 0
common interests between 2 and 3: 1
total= 1
* group 4
students: 9 0 6
common interests between 1 and 2: 1
common interests between 1 and 3: 1
common interests between 2 and 3: 1
total= 3
* total between all groups= 9