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For example, even though I have a general idea of what the periodic table is, I wouldn’t be able to name any element number off the top of my head. So, even if I had a suspicion, I probably wouldn’t remember that platinum is 78. Therefore, if we exclude the use of a search engine (which wasn’t a condition of the contest, but I believe that the tasks should be solved quickly and with at most a piece of paper at hand), there’s no difference compared to a piano – either you’re familiar with the instrument/know the exact number of platinum/that it comes before gold, or you won’t be able to guess.