Let A be an integral series {A1, A2, . . . , An}.
The zero-order series of A is A itself.
The first-order series of A is {B1, B2, . . . , Bn-1, where Bi = Ai+1 - Ai.
The ith-order series of A is the first-order series of its (i - 1)th-order series (2<=i<=n - 1).
We say A is monotonic iff A1<=A2<=. . . <=An or A1>= A2 >=. . . >= An.
A is kth-order monotonic iff all ith-order series (0<=i<=k) are monotonic, and (k + 1)th-order are not.
Specially, if the zero-order series of A is not monotonic, then A is named ugly series. If all ith-order (0<=i<=n - 1) series of A are monotonic, then A is a nice series.
Given A, determine whether it’s a ugly series or nice series. If both are not, determine k.