Description

Original problem from: NEFU 84

The Great Sage is within the Buddha's palm.

We assume the Buddha's palm is a circle with a circumference of $n$, labeled counterclockwise as: $0,1,2,\cdots ,n-1$. The Great Sage can fly a distance of $d$ each time. The Great Sage's current position is denoted as $x$, and the destination is $y$. Your task is to determine the minimum number of flights required for the Great Sage to reach the destination.

Input Format

There are multiple test cases.

The first line contains a positive integer $T$, indicating the number of test cases.
Each test case consists of a single line with four non-negative integers: the circumference of the Buddha's palm $n$, the flight distance $d$, the initial position $x$, and the destination $y$.

Note that the Great Sage's flight is always in the counterclockwise direction.

Output Format

For each test case, output a single line with the minimum number of flights required for the Great Sage to reach the destination. If it is impossible to reach the destination, output Impossible.

Sample 1

2
3 2 0 2
3 2 0 1

1
2

Constraints and Notes

For all test cases, $2\lt n\lt 10^9,0\lt d\lt n,0\le x,y\lt n$.