*X*^{2}: How many items?

You are about to enter a two columns of numbers.
The first will be your data (usually counts) *x*_{i},
the second will be your the corresponding expected results
*E*_{i}.
How many data items do you have to calculate (i.e., what is the
value of *k*)?
(There is no harm in over estimating: blanks will be
ignored. Max=99, Min=2. Note however that data and expectations
must be properly paired.)