M=20;
N=20;
K=14;
L=15;
D=50;
students=[|4,12,4,13|
11,3,12,3|
3,8,2,8|
9,17,10,17|
19,16,20,16|
3,5,3,4|
12,4,11,4|
9,18,10,18|
16,17,16,16|
16,11,15,11|
18,3,19,3|
19,4,19,3|
20,20,20,19|
10,4,11,4|
20,9,20,8|
1,14,2,14|
5,9,5,8|
20,11,19,11|
20,8,20,7|
17,4,17,5|
17,18,17,19|
8,6,8,5|
15,17,16,17|
9,5,8,5|
6,11,6,12|
5,5,4,5|
14,15,14,14|
12,20,13,20|
16,18,16,17|
11,2,11,1|
4,9,5,9|
2,9,2,10|
10,7,9,7|
15,19,16,19|
12,9,12,8|
19,1,19,2|
8,18,7,18|
9,15,9,14|
17,14,16,14|
18,12,17,12|
12,20,11,20|
8,8,9,8|
19,18,19,17|
20,2,19,2|
4,16,5,16|
1,4,2,4|
3,13,2,13|
10,9,9,9|
4,15,4,16|
9,8,9,7|];