from sys import stdin
input=lambda :stdin.readline()[:-1]

M=3*10**5+10
moebius=[0]+[1]*M
seive=[0]*2+[1]*M
for p in range(2,M):
  if seive[p]:
    for i in range(p,M,p):
      seive[i]=0
      moebius[i]*=-1
    for i in range(p*p,M,p*p):
      moebius[i]=0

Mertens=[0]*M
for i in range(1,M):
  Mertens[i]=Mertens[i-1]+moebius[i]

def calc(n,p):
  g=[0]*(n+1)
  for i in range(1,n+1):
    g[i]=(p*i)//(n*n)
  res=0
  for i in range(1,n+1):
    res+=Mertens[n//i]*g[i]
  return res

def solve():
  n,k=map(int,input().split())
  c=calc(n,n*n-1)
  if k==c+1:
    print('1/1')
    return
  if k<=c:
    rev=False
  elif k<=2*c+1:
    rev=True
    k=2*c+2-k
  else:
    print(-1)
    return
  ng,ok=-1,n*n
  while ok-ng>1:
    mid=(ok+ng)>>1
    if calc(n,mid)>=k:
      ok=mid
    else:
      ng=mid
  
  for p in range(1,n+1):
    q=(ok*p)//(n*n)
    if n*n*q>ng*p:
      if rev:
        p,q=q,p
      print(str(q)+'/'+str(p))
      return
    
  raise Exception

for _ in range(int(input())):
  solve()