code: def get_n_stacks(input_size, **_):
      n_stacks = 0
      width, height = input_size, input_size
      while width % 2 == 0 and height % 2 == 0:
          n_stacks += 1
          width = width // 2
          height = height // 2
  
      return n_stacks
  
imports: import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 1 for calling the UNet_stack obj's underlying member method code with example usage: obj.get_n_stacks(input_size) and returns: n_stacks