from math import isqrt

def solve():
    n, k = map(int, input().split())
    while k <= n:
        for d in range(1, isqrt(n)+1):
            if n%d==0 and d <= k and n//d <= k:
                break
        else:
            print(n)
            return
        n -= 1
    print(-1)
    return 

t = int(input())
for i in range(t):
    solve()