1.
Let a,b,c,da,b,c,d be numbers in the set {1,2,3,4,5,6}\{1,2,3,4,5,6\} such that the curves y=2x3+ax+by=2x^3+ax+b and y=2x3+cx+dy=2x^3+cx+d have no point in common. The maximum possible value of (ac)2+bd(a-c)^2+b-d is