Solve the programming task below in a Python markdown code block.
Chef's current score is X. Each second, Chef will find the smallest [prime factor] of his score and add it to his score.

Determine the minimum time in seconds, after which his score becomes ≥ Y.

------ Input Format ------ 

- The first line of input will contain a single integer T, denoting the number of test cases.
- Each test case consists of a single line containing two integers X and Y, the initial and required score of Chef.

------ Output Format ------ 

For each test case, output the minimum time in seconds, after which Chef's score becomes ≥ Y.

------ Constraints ------ 

$1 ≤ T ≤ 1000$
$2 ≤ X ≤ 10$
$20 ≤ Y ≤ 10^{9}$

----- Sample Input 1 ------ 
4
2 23
9 20
5 100
6 89

----- Sample Output 1 ------ 
11
5
46
42

----- explanation 1 ------ 
Test case $1$: The initial score is $2$. Chef needs the score to be at least $23$. 
- The smallest prime factor of $2$ is $2$. Thus, the score increase to $2+2 = 4$.  
- The smallest prime factor of $4$ is $2$. Thus, the score increase to $4+2 = 6$.
- Similarly, each time the score would be increased by $2$. Thus, after $11$ seconds, the score becomes $24$, which is $≥ 23$.

Test case $2$: The initial score is $9$. Chef needs the score to be at least $20$. 
- The smallest prime factor of $9$ is $3$. Thus, the score increase to $9+3 = 12$.  
- The smallest prime factor of $12$ is $2$. Thus, the score increase to $12+2 = 14$.
- The smallest prime factor of $14$ is $2$. Thus, the score increase to $14+2 = 16$.
- The smallest prime factor of $16$ is $2$. Thus, the score increase to $16+2 = 18$.
- The smallest prime factor of $18$ is $2$. Thus, the score increase to $18+2 = 20$.

Thus, after $5$ seconds, the score becomes $20$, which is $≥ 20$.