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Division Problem
##### Submissions: 291   Accuracy: 30.24%   Difficulty: Easy   Marks: 2

You will be given two positive integers A and N and you have to find the smallest positive integer x such that N divides Ax - 1.

Input:
The first line of input contains a single integer T denoting the number of test cases.Then T test cases follow. The first and only line of each test case consists of two space separated positive integers denoting A and N.

Output:
Corresponding to each test case, in a new line, print the smallest positive number x such that N divides Ax - 1. If it is not possible to find such a number x, then print -1.

Constraints:
1 ≤ T ≤ 100
1 ≤ N,A ≤ 10000

Example:
Input:
3
10 8
7 16
5 18

Output:
-1
7
11

#### ** For More Input/Output Examples Use 'Expected Output' option **

Author: Hemang Sarkar

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