Added 67.py

[anmolgup]

Fixes #{ISSUE_NUMBER}

• [x] Pull Request Title is of form Problem Number [Language].
• [ ] This problem already had an entry in this repository.
• [ ] This solution is better than the one already in this repository.
• [x] This solution is prepared by me and not copied from anywhere else on the web.
• [x] I have added a BY:{Your Hackerrank username} copyright comment in my solution.
• [x] I have updated index.md file (In appropriate folder in the appropriate manner).
• [x] I understand that pull request will be closed if I failed to update it even once in a week.