Alan does a weekly exercise program consisting of cardiovascular work and weight training. Each week, he exercises for at least 6 hours. He spends at most 4 hours doing cardiovascular work. He spends at most 10 hours on weight training. Let x denote the time (in hours) that Alan spends doing cardiovascular work. Let y denote the time (in hours) that he spends on weight training. Shade the region corresponding to all the value of x and y that satisfy these requirements.