Update README

Author: milancurcic

README.md

@@ -33,7 +33,7 @@ Read the paper [here](https://arxiv.org/abs/1902.06714).
 | Dense (fully-connected) | `dense` | `input1d`, `flatten` | 1 | ✅ | ✅ |
 | Convolutional (2-d) | `conv2d` | `input3d`, `conv2d`, `maxpool2d`, `reshape` | 3 | ✅ | ✅(*) |
 | Max-pooling (2-d) | `maxpool2d` | `input3d`, `conv2d`, `maxpool2d`, `reshape` | 3 | ✅ | ✅ |
-| Flatten | `flatten` | `input3d`, `conv2d`, `maxpool2d`, `reshape` | 1 | ✅ | ✅ |
+| Flatten | `flatten` | `input2d`, `input3d`, `conv2d`, `maxpool2d`, `reshape` | 1 | ✅ | ✅ |
 | Reshape (1-d to 3-d) | `reshape` | `input1d`, `dense`, `flatten` | 3 | ✅ | ✅ |
 
 (*) See Issue [#145](https://github.com/modern-fortran/neural-fortran/issues/145) regarding non-converging CNN training on the MNIST dataset.