7-14 求整数段和

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int a=sc.nextInt(),b=sc.nextInt(),s,n=0;
        s=(a+b)*(b-a+1)/2;
        for(;a<=b;a++,n++){
            if(n>4){
                System.out.println("");
                n=0;
            }
            System.out.print(String.format("%5d",a));
        }
        System.out.print("\nSum = "+s);
    }
}