import sys input = lambda :sys.stdin.readline()[:-1] ni = lambda :int(input()) na = lambda :list(map(int,input().split())) yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES") no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO") ####################################################################### def divisors(n): lower_divisors , upper_divisors = [], [] i = 1 while i*i <= n: if n % i == 0: lower_divisors.append(i) if i != n // i: upper_divisors.append(n//i) i += 1 return lower_divisors + upper_divisors[::-1] for _ in range(ni()): n, k = na() for i in range(n, k, -1): if all(x > k or i // x > k for x in divisors(i)): print(i) break else: print(-1)