for _ in range(int(input())):
    n, m = map(int, input().split())
    if m == 1:
        print(0)
    if n >= m:
        print(m // 2)
    else:
        l = m - n - 2
        print(m // 2 - (m - n) + (2 + m - n) * l // 2 + l)