[백준/Java] 3046번 R2

-코드

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		int r1 = sc.nextInt();
		int s = sc.nextInt();
		
		System.out.println(s * 2 - r1);
 	}	
}