Hy, i need to write a date and the formula to show me the day.

Example:

a b
1 11.06.2008 monday
2 06.06.2008 friday
3 saturday !!!!!problem

The formula is in "b" cell. I use this formula and its working but if i dont
write anything in cell "a", the formula show me "saturday". I dont want
anything to show in "b" cell unless i write something in "a" cell.

Thanks in advance.