diff --git a/README.md b/README.md
index 4619d3a..309ac03 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,8 @@
 `$ export COOK=" ... "`
 
 ### __Notes__
-- 33/ --- _quite possibly a knapsack problem_
+- 33/ coin chain / knapsack problem
+- 21/ shortest / min cost path - Dijkstra
 - 18/ hour arithmetic - add 1 or -1 second
 - 17/ date arithmetic - `currdate.Sub(prevdate)` 
 - 15/ bidirectional BFS