First choose the number of cities by typing ‘1’, ‘3’, ‘5’, ‘010’ (so as not to choose 1), or ’25’ – then type in the largest N cities per country where N was the number you chose. I have the largest city for every country regardless of population. For the rest of the cities I had a minimum pop of 10K for every continent (incl Oceania) except Asia & Africa which have a 50K minimum population.