题解 | 牛牛的等差数列

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int a = in.nextInt();
        int b = in.nextInt();
        if(a > b){
            int c = (a - b);
            int d = b - c;
            System.out.println(d); 
        }else{
            int c = (b - a);
            int d = b + c;
            System.out.println(d);
        }
    }
}