And also make sure to distinguish between your pi's and your n's! I can't count the number of times I've mixed the two up while finding Fourier coefficients.
This is why I exaggerate the pi's top cross (like a capital T with two legs). A lot of people write pi in a way such that the top cross has no dangling edges[0]. I always try to exaggerate the unique features of symbols. One can avoid a lot of these problems by first exhausting the least overlapping symbols.
[0] See left variant: https://pm1.narvii.com/6331/cb50e106b141735ad714b934eb18ea55...