# No.897 compαctree
q = int(input())
n = []
k = []

for i in range(q):
    tmp = [int(s) for s in input().split()]
    n.append(tmp[0])
    k.append(tmp[1])

for i in range(q):
    depth = 1
    points = 1

    while points < n[i]:
        points += k[i] ** depth
        depth += 1

    print(depth - 1)