from typing import List


def calc_diff(arr1: List[List[str]], arr2: List[List[str]]) -> List[int]:
  """Calculate positionwise difference of two List of List of iterables(eg. List of List of strings). This is used for plotting the avalanche effect induced during each round of DES."""
  diff = []
  for i in range(len(arr1[0])):
    cnt = 0
    for j in range(len(arr1)):
      for (c,d) in zip(arr1[j][i], arr2[j][i]):
        if(c != d):
          cnt += 1
    diff.append(cnt)
  return diff