400
The Jews were allowed to travel this total distance on the Sabbath according to the Law.
What is 2000 cubics/paces? (Joshua 3:4-5) - interpretation
also acceptable answer...
What is zero distance? According to the Mosaic law every Israelite was forbidden to travel on the Sabbath day.
Exodus 16:29 "See, for the Lord hath given you the Sabbath, therefore he giveth you on the sixth day the bread of two days; abide ye every man in his place, let no man go out of his place on the seventh day."