{Total} = {M} + {N} - {Both}
{Total} = 42 + 28 - 12 = 58.
There are 42 distinct numbers in set M, there are 28 distinct numbers in set N, and there are 12 distinct numbers that are in both sets M and N. Set H is the set containing the elements that are in at least one of sets M and N. How many elements are in set H?

a: 39
b: 40
c: 51
d: 58
e: 63