Day 2 update


Former-commit-id: 55dd32963a44943ce7a1dc15c7686728f83865c8
Day2


Former-commit-id: 8afd534ba1cbefb3d4ae2e76a87f7db6c0f74841
Day3


Former-commit-id: 1b1523e309ce686dc5525439f55b98d7ce61800d
day 1 folder