SP19274 BLOPER - Operators

Given a set of N integer A = {1, 2, 3, …, N} and a integer S, your task is find a way to insert an operator ‘+’ or ‘-‘ to every neighbor pair of A, that the result of the expression after insert equal to S.

A single line, N and S (1

If there are way(s) to insert, outputs any of them, otherwise outputs “Impossible” (without quotes).