from math import isqrt

def solve():
	N, K = map(int, input().split())
	
	def isgood(x):
		for d in range(1, isqrt(x)+1):
			if x%d: continue
			if d <= K and x/d <= K:
				return False
		return True
	
	for x in range(N, max(0, N-300), -1):
		if isgood(x):
			print(x)
			return
	print(-1)

T = int(input())
for _ in range(T):
	solve()