Don’t mislead others. “-” is not a constant definition character at all. If 12 is not the answer, it may be a typographical error. Grammatically speaking, there is no difference between 12 and -20, and they can both be considered integer constants. .

Of course, l2 is not (l is the lower case of L, is this possible?) Note that 12 in the question is 12. (There is a decimal point after it), it can really fool people