diff --git a/README.md b/README.md
index 27176ed..f0bd6a9 100644
--- a/README.md
+++ b/README.md
@@ -24,13 +24,13 @@ You can use [pip][3] to install the dependencies via:
 
 I'll be distributing this code with a file EXAMPLE.csv. Try running
 
-    python makePlan.py 4 EXAMPLE.csv out/ output.pkl
+    python makePlan.py -n 4 EXAMPLE.csv out/ output.pkl
 
-This will put a bunch of files into the "out/" directory (see OUTPUT FILE LIST)
+where "out/" must already exist. This will put a bunch of files into the "out/" directory (see OUTPUT FILE LIST).
 
 Now try running
 
-    python makePlan.py 3 out/output.pkl
+    python makePlan.py -n 3 out/output.pkl
 
 This uses the plan stored in output.pkl instead of calculating a new one. It will create files for 3 agents instead of 4.
 
@@ -77,11 +77,11 @@ No promises
 
 # Usage
 
-    python makePlan.py [-b] agent_count input_file [output_directory] [output_file]
+    python makePlan.py [-b] -n agent_count input_file [output_directory] [output_file]
 
-    -b:          Include this option if you like your maps blue instead of green for any reason
+    -b: Include this option if you like your maps blue instead of green for any reason
 
-    agent_count: Number of agents for which to make a plan
+    -n agent_count: Number of agents for which to make a plan
 
     input_file:  One of two types of files:
         .csv   format: