import copy

# Original list with a nested list
original_list = [1, [2, 3], 4]

# Create a deep copy of the original list
deep_copied_list = copy.deepcopy(original_list)

print(f'Original list before modification: {original_list}')
print(f'Deep copied list before modification: {deep_copied_list}
')

# Modify an element in the nested list of the deep copy
deep_copied_list[1][0] = 'X'

print(f'Original list after deep copy modification: {original_list}')
print(f'Deep copied list after modification: {deep_copied_list}')