def divisor(n, flag=1):
  _ret = []
  for i in range(1, int((n)**0.5)+1):
    if n%i == 0:
      _ret.append(i)
      if i*i != n: _ret.append(n//i)
  if flag:
    _ret.sort()
  return _ret

for _ in range(int(input())):
  N, K = map(int, input().split())
  if N > K**2:
    print(N)
  else:
    for x in range(N, K, -1):
      div = divisor(x)
      n = len(div)
      y = div[n//2]
      if y > K:
        print(x)
        break
    else:
      print(-1)