(A) ---> 
[[1,3,5]
 [2,4,6]
 [3,5,7]]
(max_element(A)) ---> 7
(sum(A)) ---> 36
(B) ---> 
[[0,-1,-2]
 [1,0,-1]
 [2,1,0]]
(min_element(B)) ---> -2
(sum(B)) ---> 0
(make_matrix(A+10*B)) ---> 
[[1,-7,-15]
 [12,4,-4]
 [23,15,7]]
(max_element(A+10*B)) ---> 23