param n:=9;

set BOX[1] := (1,1) (1,2) (1,3) (2,1) (2,2) (2,3) (3,1) (3,2) (3,3);
set BOX[2] := (1,4) (1,5) (1,6) (2,4) (2,5) (2,6) (3,4) (3,5) (3,6);
set BOX[3] := (1,7) (1,8) (1,9) (2,7) (2,8) (2,9) (3,7) (3,8) (3,9);
set BOX[4] := (4,1) (4,2) (4,3) (5,1) (5,2) (5,3) (6,1) (6,2) (6,3);
set BOX[5] := (4,4) (4,5) (4,6) (5,4) (5,5) (5,6) (6,4) (6,5) (6,6);
set BOX[6] := (4,7) (4,8) (4,9) (5,7) (5,8) (5,9) (6,7) (6,8) (6,9);
set BOX[7] := (7,1) (7,2) (7,3) (8,1) (8,2) (8,3) (9,1) (9,2) (9,3);
set BOX[8] := (7,4) (7,5) (7,6) (8,4) (8,5) (8,6) (9,4) (9,5) (9,6);
set BOX[9] := (7,7) (7,8) (7,9) (8,7) (8,8) (8,9) (9,7) (9,8) (9,9);

set FIX :=
(1,1,1)
(1,4,5)
(1,5,6)
(1,6,4)
(1,8,2)
(2,1,2)
(2,2,6)
(2,6,9)
(2,7,8)
(3,4,3)
(3,6,8)
(4,5,5)
(5,4,4)
(5,5,7)
(5,6,3)
(5,9,2)
(6,3,9)
(6,7,3)
(7,1,3)
(7,2,2)
(7,7,1)
(7,9,7)
(8,1,9)
(8,2,5)
(8,6,7)
(9,1,7)
(9,2,4)
(9,4,2)
(9,6,1)
(9,8,6);