The data for the number of hand-held gaming devices sold for the past 5 weeks are 20 units, 15 units, 25 units, 31 units, and 16 units respectively. The time series appears to be relatively stable, without trend, seasonal, or cyclical effects; thus, a moving average model would be appropriate. The simple moving average value of k is set at 2. What is the difference between the actual value and the forecasted for the 3rd week (rounded to the nearest integer)?