A1 Carpet cleaners charges $75 to clean the first 200 sq ft of carpet. There’s an additional charge of $.25 per square foot for any what is that exceeds 200 sq ft and $1.40 per step for any carpeting on a staircase. A customers cleaning bill was $253.95. This included the cleaning of a staircase with 13 steps. In addition to the staircase, how many square feet of carpet did the customer have cleaned?