Distinct Pair Sums CodeChef Solution

Problem 

You are given a range of integers $\{L, L+1, \ldots, R\}$. An integer $X$ is said to be reachable if it can be represented as a sum of two not necessarily distinct integers in this range. Find the number of distinct reachable integers.

Input

• The first line of the input contains a single integer $T$ denoting the number of test cases. The description of $T$ test cases follows.
• The first and only line of each test case contains two space-separated integers $L$ and $R$.

Output

For each test case, print a single line containing one integer — the number of reachable integers.

Constraints

• $1 \leq T \leq 10^5$
• $1 \leq L \leq R \leq 10^6$

Sample 1:

Input

Output

2
2 2
2 3

1
3

Explanation:

Example case 1: The only reachable integer is $2 + 2 = 4$.

Example case 2: $4$, $5$ and $6$ are reachable, since $2+2=4$, $2+3=5$ and $3+3=6$.

ANSWER