Calculate the number 306

While living in Denver the weatherman said, expect 10 to 12 inches of snow tonight so park on the right side of the road so we can plow the left side. Willie’s wife ran out and parked on the right side. The next week the forecast called for another 10 to 12 inches of snow, but this time he said park on the left side. So Willie’s wife ran out and parked the car on the left side of the road. The following week he said 16 inches of snow expected park, the lights went out and all our power was lost. Willie’s wife said, my goodness, now I don’t know where to park the car. “Why don’t you just leave it in the garage!” Willie said.