Update README.md

tackle word misspelling issue

README.md

@@ -61,7 +61,7 @@ We support demo for image/ image folder, video, and webcam.
 
 First, download the models (By default, [ctdet_coco_dla_2x](https://drive.google.com/open?id=1pl_-ael8wERdUREEnaIfqOV_VF2bEVRT) for detection and 
 [multi_pose_dla_3x](https://drive.google.com/open?id=1PO1Ax_GDtjiemEmDVD7oPWwqQkUu28PI) for human pose estimation) 
-from the [Model zoo](readme/MODEL_ZOO.md) and put them if `CenterNet_ROOT/models/`.
+from the [Model zoo](readme/MODEL_ZOO.md) and put them in `CenterNet_ROOT/models/`.
 
 For object detection on images/ video, run:
 
@@ -133,4 +133,4 @@ If you find this project useful for your research, please use the following BibT
       author={Zhou, Xingyi and Wang, Dequan and Kr{\"a}henb{\"u}hl, Philipp},
       booktitle={arXiv preprint arXiv:1904.07850},
       year={2019}
-    }
+    }