import sys
stdin = sys.stdin
 
ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
nn = lambda: list(stdin.readline().split())
ns = lambda: stdin.readline().rstrip()

n = ni()

if n == 1:
  print('1')
  exit()
if n == 2:
  print('3')
  exit()

m = 2
i = 2
for h in range(3,1000000000):
  o = m + (h-2)*(h-1)//2+1
  #print(o,h)
  if o > n:
    i = h
    break
  m = o

aa = []
i -= 2
for j in range(i+1):
  for k in range(i-j+1):
    a = '1'
    a += '1'*k
    a += '0'*j
    a += '1'*(i-j-k)
    a += '1'
    aa.append(int(a,2))
    if j == 0:
      break

aa.sort()

print(aa[n-m-1])