is somebody knows how many validation file there are?

I execute blow commands: git clone https://huggingface.co/datasets/cerebras/SlimPajama-627B python scripts/prepare_slimpajama.py --source_path /path/to/SlimPajama --tokenizer_path data/llama --destination_path data/slim_star_combined --split validation --percentage 1.0 only got 257 validation file, i wonder is there some mistake