Building A and building B are 500 meters apart. There is no road between them, so to drive from building A to building B, it is necessary to first drive to building C and then to building B. Triangle A B C is shown. Angle A C B is 90 degrees and angle A B C is 60 degrees. The length of side B C is a, the length of C A is b, and the length of hypotenuse A B is 500 meters.

About how much farther is it to drive than to walk directly from building A to building B? Round to the nearest whole number.