25 gaps,1,4,Fst lost,2,3,5,6 fist want to win or lose OK.Induction: 3k+1 Fst lost, 3k+2,3 Fst can win or lost, Fst first step,let 1) two sides are 3t and 3x+2 2)3t and 3x
3)3t+1 and 3x+1 4)3t+1 and 3x+2. 1),2),4),Scd alway constract 3 areas n,n,3h+1,Scd win.3)Scd win.