import sys
input=sys.stdin.readline
def isPrimeMR(n):
  d = n - 1
  d = d // (d & -d)
  L = [2, 3, 61]
  for a in L:
    t = d
    y = pow(a, t, n)
    if y == 1: continue
    while y != n - 1:
      y = (y * y) % n
      if y == 1 or t == n - 1: return 0
      t <<= 1
  return 1
for _ in range(int(input())):
  a,p=map(int,input().split())
  if isPrimeMR(p):print(1)
  else:print(-1)