Java 代码

import java.util.Scanner;
public class Main
{
    public static void main(String[] args)
    {
        Scanner sca=new Scanner(System.in);
        int a=sca.nextInt();  //读取a,b,c,d; 
        int b=sca.nextInt();
        int c=sca.nextInt();
        int d=sca.nextInt();
        int ans=a*b-c*d;
        System.out.println("DIFERENCA = "+ans);

    }
}