N=gets.chomp.to_i

def match(n)
  # 6 => 9
  # 5 => 5
  # 4 => 4
  # 3 => 7
  # 2 => 1
  # 1 か 7しかない
  seven = n % 2 == 1
  c = -1
  while n > 0
    c += 1
    n = n >> 1
  end
  puts c
  ret = 0
  for num in 0..c-1
    if num == (c-1) and seven
      ret += 10 ** num * 7
    else
      ret += 10 ** num
    end
  end
  return ret
end

puts match(N)