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

def quotient_range(n):
  ret=[]
  i=1
  while i<=n:
    q=n//i
    j=n//q+1
    ret.append((i,j))
    i=j
  return ret

def floor_sum(n,m,a,b):
  ans=0
  while True:
    if a>=m:
      ans+=(n-1)*n*(a//m)//2
      a%=m
    if b>=m:
      ans+=n*(b//m)
      b%=m
    y_max=(a*n+b)//m
    x_max=(y_max*m-b)
    if y_max==0:
      return ans
    ans+=(n-(x_max+a-1)//a)*y_max
    n,m,a,b=y_max,a,m,(a-x_max%a)%a
    
def count(n,L,R,p):
  return floor_sum(R-L,n*n,p,L*p)

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 solve():
  n,k=map(int,input().split())
  QR=quotient_range(n)
  c=0
  for L,R in QR:
    c+=count(n,L,R,n*n-1)*Mertens[n//L]
  
  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
    cnt=0
    for L,R in QR:
      cnt+=count(n,L,R,mid)*Mertens[n//L]
    if cnt>=k:
      ok=mid
    else:
      ng=mid
  
  ng2,ok2=0,n
  while ok2-ng2>1:
    mid=(ok2+ng2)>>1
    cnt1=floor_sum(mid,n*n,ok-1,ok-1)
    cnt2=floor_sum(mid,n*n,ok,ok)
    if cnt1!=cnt2:
      ok2=mid
    else:
      ng2=mid
  
  den=ok2
  num=ok*den//(n*n)
  if rev:
    den,num=num,den
  print(str(num)+'/'+str(den))
  
for _ in range(int(input())):
  solve()