Exercise 2. For any pair of positive integers \(m\) and \(n\), let \(Z_m + Z_n = \{(a,b) | a \in Z_m, b \in Z_n\}\). For any pair of elements \((a,b)\) and \((c,d)\) in \(Z_m + Z_n\) define \((a,b) + (c,d) = ((a+c)\; mod\; m, (b+d)\; mod\; n)\). [For example, in
\(Z_3 + Z_4\), we have (1,2) + (3,4) = (0,1).] This software checks whether or not \(Z_m + Z_n\) is cyclic. Run the program for the following choice for \(m\) and \(n\): (2,2), (2,3), (2,4), (2,5), (3,4), (3,5), (3,6), (3,7), (3,8), (3,9) and (4,6). On the basis of this output, guess how \(m\) and \(n\) must be related for \(Z_m + Z_n\) to be cyclic.

Please enter \(m\) and \(n\).