public class Tax{
    public static void main(String[] args) {
        // 给一个有工资收入和稿费收入的小伙伴算税:        
        Income gongzi = new Salary();        
        Income gaofei = new Gaofei();        
        System.out.println(gongzi.run(8000) +  gaofei.run(28500));    
    }
}

abstract class Income {
    public abstract double run(double money);
}

class Salary extends Income {
    @Override
    public double run(double income){
        if (income <= 5000) {
            return 0;        
        }
        return (income - 5000) * 0.2;    
    }
}
class Gaofei extends Income{
    @Override
    public double run(double income){
        if(income < 4000){
            return (income-800) * 0.7 * 0.2;        
        }
        return income * (1 - 0.2) * 0.7 *0.2;    
    }
}