D = gets.to_i

def f(x)
  len = 0

  while x > 0
    len += x
    x /= 2
  end

  len
end

ng = 0
ok = 10 ** 18

while (ok - ng).abs >= 2
  x = (ok + ng) / 2

  if D <= f(x)
    ok = x
  else
    ng = x
  end
end

if f(ok) != D
  puts D
else
  puts ok
end