import sys
input=sys.stdin.readline
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))

def main():
    mod=10**9+7
    T=I()
    #nまでの素数を列挙(n loglogn)
    n = 5*(10**6)+10

    #is_prime[i]にはi-1が素数か否かを示すboolが入る，[0]に1の素数判定がある．
    is_prime = [True]*(n+1)
    is_prime[0] = False

    for i in range(2, n+1):
        if is_prime[i-1]:
            j = 2 * i
            while j <= n:
                is_prime[j-1] = False
                j += i

    for i in range(T):
        A,P=MI()
        if is_prime[P+1]==1:
            if A%P==0:
                print(0)
            else:
                print(1)
        else:
            print(-1)


main()