import os
original_name = os.listdir('.')[0]
print("original name:", original_name)
if original_name.upper() != original_name:
    changed_name = original_name.upper()
else:
    changed_name = original_name.lower()
print("changed name:", changed_name)
if os.path.exists(changed_name):
    print("case-insensitive")
else:
    print("case-sensitive")