updated comments
Revert "updated problems"

This reverts commit bdba7c20943d59c055493e2de3bdc089b2efaa86.
Revert "Revert "updated problems""

This reverts commit 11298f5bf181b1f24c343c1b49fe11e8c46fc445.
Revert "updated comments"

This reverts commit 32823eaef2f289545fcaf0f0de522f6de23162e7.