def judge(k, N):
	g = [i * k // N ** 2 for i in range(N + 1)]
	f = g.copy()
	ans = 0
	for i in range(1, N + 1):
		for j in range(i * 2, N + 1, i):
			f[j] -= f[i]
		ans += f[i]
	return ans
def solve(N, K):
	key = judge(N ** 2 - 1, N) + 1
	if key == K:
		return [1, 1]
	elif key * 2 - 1 < K:
		return [-1]
	elif key < K:
		return solve(N, 2 * key - K)[::-1]
	m = [0, N ** 2]
	while m[1] - m[0] > 1:
		mid = sum(m) // 2
		m[judge(mid, N) >= K] = mid
	for d in range(1, N + 1):
		n = d * m[1] // N ** 2
		if n * N ** 2 > d * m[0]:
			return [n, d]
T = int(input())
for i in range(T):
	N, K = map(int, input().split())
	print('/'.join(list(map(str,solve(N, K)))))