import java.lang.*;
interface ToolSpeed
{
    public double speed(double a,double b,double c);
}

   
class  Car007 implements ToolSpeed
{
        public double speed(double a,double b,double c)
    {
        return a*b/c;
    }
}
class Plane implements ToolSpeed
{
    public double speed(double a,double b,double c)
    {
        return a+b+c;
    }
}
public class ComputeTime
{
    public static void main(String args[])
    {
        try
        {
        ToolSpeed   ts=(ToolSpeed)Class.forName(args[0]).newInstance();
        double a=Double.parseDouble(args[1]);
        double b=Double.parseDouble(args[2]);
        double c=Double.parseDouble(args[3]);
        System.out.println("the time is "+1000/ts.speed(a,b,c));
        System.out.println("\n");
        }
              catch(Exception e)
                {
                 System.out.println("class not found");
           }
        
    }
}
ToolSpeed   ts=(ToolSpeed)Class.forName(args[0]).newInstance();这句话不明白是什么意思