Minimal Coprime

Today, Little John used all his savings to buy a segment. He wants to build a house on this segment.

A segment of positive integers $[l,r]$ is called coprime if $l$ and $r$ are coprime1.

A coprime segment $[l,r]$ is called minimal coprime if it does not contain2 any coprime segment not equal to itself. To better understand this statement, you can refer to the notes.

Given $[l,r]$, a segment of positive integers, find the number of minimal coprime segments contained in $[l,r]$.

1Two integers $a$ and $b$ are coprime if they share only one positive common divisor. For example, the numbers $2$ and $4$ are not coprime because they are both divided by $2$ and $1$, but the numbers $7$ and $9$ are coprime because their only positive common divisor is $1$.

2A segment $[l',r']$ is contained in the segment $[l,r]$ if and only if $l \le l' \le r' \le r$.

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 100$). The description of the test cases follows.

The only line of each test case consists of two integers $l$ and $r$ ($1 \le l \le r \le 10^9$).

For each test case, output the number of minimal coprime segments contained in $[l,r]$, on a separate line.

On the first test case, the given segment is $[1,2]$. The segments contained in $[1,2]$ are as follows.

• $[1,1]$: This segment is coprime, since the numbers $1$ and $1$ are coprime, and this segment does not contain any other segment inside. Thus, $[1,1]$ is minimal coprime.
• $[1,2]$: This segment is coprime. However, as it contains $[1,1]$, which is also coprime, $[1,2]$ is not minimal coprime.
• $[2,2]$: This segment is not coprime because $2$ and $2$ share $2$ positive common divisors: $1$ and $2$.

Therefore, the segment $[1,2]$ contains $1$ minimal coprime segment.