import java.util.Scanner;

public class HelloWorld {

	    public static void main(String[] args) throws Exception {

	    	Scanner sc = new Scanner(System.in);
	    	int n = sc.nextInt();
	    	int x = sc.nextInt();
	    	int sum = 0;

	    	for (int i=0; i < n; i ++) {
	    		sum += sc.nextInt();
	    	}
	    	sc.close();

	    	System.out.println(- (n - 1) * x + sum);
	    	}

	    }