How assign max value of subtotal to the interval of the horizontal axis

I want assign max value of subtotal of a field to the interval of the horizontal axis.

for eg There is a column name newsub which has subtotal sum(newsub). I want to assign max value of sum(newsub) to the interval of vertical axis in the line graph. I tried interval: =Max(Sum(Fields!Sales.Value,"Dataset1")), =Max(Sum(Fields!Sales.Value,"groupbydate"))