Giải bài trực tuyến

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.

Input

A single line, N and S (1 ≤ N ≤ 500, |S| ≤ 125250)

Output

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

Example

Input:
9 5

Output:
1-2+3-4+5-6+7-8+9

Input:
5 6

Output:
Impossible