Alice and Bob play the following game. They write some fractions of the form 1/n, where n is positive integer, onto the blackboard. The first move is made by Alice. Alice writes only one fraction in each her turn and Bob writes one fraction in his first turn, two fractions in his second turn, three fractions in his third turn and so on. Bob wants to make the sum of all the fractions on the board to be an integer number after some turn. Can Alice prevent this?Andrey Arzhantsev gamecombinatoricsTournament of Towns