import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		long x = sc.nextInt();
		int[] s = new int[n];
		for (int i = 0; i < n; i++) {
			s[i] = sc.nextInt();
		}
		sc.close();

		long sum = 0;
		for (int i = 0; i < n; i++) {
			sum += s[i];
		}

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