def stern_brocot_tree_search(max_val):
  lower=(1,1)
  upper=(0,1)
  now=(1,1)
  while True:
    now=(lower[0]+upper[0],lower[1]+upper[1])
    now_judge=judge_function(now)
    if now_judge:
      frm=lower
      to=upper
    else:
      frm=upper
      to=lower
    
    L=1
    R=2
    while judge_function((frm[0]+R*to[0],frm[1]+R*to[1]))==now_judge:
      L*=2
      R*=2
      if frm[0]+L*to[0]>max_val or frm[1]+L*to[1]>max_val:
        return to
    while L+1<R:
      mid=(L+R)//2
      if judge_function((frm[0]+mid*to[0],frm[1]+mid*to[1]))==now_judge and frm[0]+mid*to[0]<=max_val and frm[1]+mid*to[1]<=max_val:
        L=mid
      else:
        R=mid
    
    if now_judge:
      lower=(frm[0]+L*to[0],frm[1]+L*to[1])
    else:
      upper=(frm[0]+L*to[0],frm[1]+L*to[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 mertens_table(n):
  if n==0:
    return [[0],[0]]
  b=10**4
  small=[1]*(n//b+1)
  large=[1]*(b+1)
  small[0]=0
  large[0]=0
  
  prime=[1]*(n//b+1)
  for p in range(2,n//b+1):
    if not prime[p]:
      continue
    for j in range(p,n//b+1,p):
      if j>p:
        prime[j]=0
      if j%(p*p)==0:
        small[j]=0
      else:
        small[j]*=-1
  
  for i in range(1,n//b):
    small[i+1]+=small[i]
  
  for i in range(b,0,-1):
    l=2
    while l<=n//i:
      q=n//(i*l)
      r=n//(i*q)+1
      if i*l<=b:
        large[i]-=large[i*l]*(r-l)
      else:
        large[i]-=small[n//(i*l)]*(r-l)
      l=r
  return small,large

def range_g(L,R,P,Q):
  return floor_sum(R-L,Q,P,L*P)

def count(n,P,Q):
  res=0
  for L,R in QR:
    x=n//L
    if x<len(small):
      res+=small[x]*range_g(L,R,P,Q)
    else:
      res+=large[n//x]*range_g(L,R,P,Q)
  return res

def judge_function(res):
  P,Q=res
  return count(n,P,Q)>=k

for _ in range(1):
  n,k=map(int,input().split())
  small,large=mertens_table(n)
  QR=quotient_range(n)
  c=count(n,n-1,n)
  if k==c+1:
    print('1/1')
    continue
  if k<=c:
    rev=False
  elif k<=2*c+1:
    rev=True
    k=2*c+2-k
  else:
    print(-1)
    continue
  ans=stern_brocot_tree_search(n)
  num,den=ans
  if rev:
    den,num=num,den
  print(str(num)+'/'+str(den))