human
PYTHON3 solution for "You are given two integers l and r, l≤ r. Find the largest possible value of a mod b over all pairs (a, b) of integers for which r≥ a ≥ b ≥ l.

As a reminder, a mod b is a remainder we get when dividing a by b. For example, 26 mod 8 = 2.

Input

Each test contains multiple test cases.

The first line contains one positive integer t (1≤ t≤ 10^4), denoting the number of test cases. Description of the test cases follows.

The only line of each test case contains two integers l, r (1≤ l ≤ r ≤ 10^9).

Output

For every test case, output the largest possible value of a mod b over all pairs (a, b) of integers for which r≥ a ≥ b ≥ l.

Example

Input

4
1 1
999999999 1000000000
8 26
1 999999999

Output

0
1
12
499999999

Note

In the first test case, the only allowed pair is (a, b) = (1, 1), for which a mod b = 1 mod 1 = 0.

In the second test case, the optimal choice is pair (a, b) = (1000000000, 999999999), for which a mod b = 1.":



Write me a Python code to find the largest possible value of a mod b over all pairs (a, b) of integers for which r≥ a ≥ b ≥ l?
assistant
#Here is Python code to find the largest possible value of a mod b over all pairs (a, b) of integers for which r≥ a ≥ b ≥ l.
 def mex(L,R):
    if L == R:
        T = 0
    elif L*2<R:
        if R%2:
            T = R//2
        else:
            T = (R//2)-1
    else:
        if R%L==0:
            L+=1
        T = R%L
    return T
N = int(input())
Z = []
for q in range(N):
    l, r = list(map(int, input().split()))
    Z.append(mex(l,r))
for me in Z:
    print(me)