We describe our two NMT systems submitted to the WMT2021 shared task in English-Czech news translation: CUNI-DocTransformer (document-level CUBBITT) and CUNI-Marian-Baselines. We improve the former with a better sentence-segmentation pre-processing a
nd a post-processing for fixing errors in numbers and units. We use the latter for experiments with various backtranslation techniques.
