java 输入两个坐标输出两点间距离

import java.util.Scanner;

class Main {

   public static void main(String[] args) {

      Scanner input = new Scanner(System.in);
      // code here
      int x1=input.nextInt();
        int y1=input.nextInt();
        int x2=input.nextInt();
        int y2=input.nextInt();
        double len=Math.sqrt(Math.pow((x1-x2),2)+Math.pow((y1-y2),2));
        double a=len*10;
        if(a%10>=5){
            System.out.println((int)len+1);
        }else
            System.out.println((int)len);

      input.close();
   }
}