A=set()
N=int(input())
from math import sqrt
k=int(sqrt(N))
for x in range(1,k+1):
  t=N%x
  u=x-t
  f=u*(x+1)
  if f<N:
    A.add(x)
for y in range(2,k+1):
  x=N//y
  t=N%x
  u=x-t
  f=u*(x+1)
  if f<N:
    A.add(x)
result=0
for x in A:
  t=N%x
  u=x-t
  p=(N-u*(x+1))//x
  result+=(p+x)//(x+1)
print(result)