diff --git a/README.md b/README.md
index 13aabfd2ca85e1ac4553eac9b6b4a3d3afbdaf8b..01d86c0215a9ea18d2c2e625839ffe90a7564e5b 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ action space. The reduced action space just removes DO_NOTHING.
 
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 The used policy is based on the FastTreeObs in the official starter kit - NeurIPS 2020 Flatland Challenge. But the
- FastTreeObs in this repo is extended version. 
+ FastTreeObs in this repo is an extended version. 
 [fast_tree_obs.py](./utils/fast_tree_obs.py)
 
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