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 k = sc.nextInt();
	    	int[] ai_Array = new int[n];
	    	for (int i = 0; i < n; i ++) {
	    		ai_Array[i] = sc.nextInt();
	    	}
	    	sc.close();

	    	double sum_all = 0;
	    	int sum_bit = 0;
	    	for (int i = n - 1; i >= 0; i -- ) {
	    		sum_all += ai_Array[i] * Math.pow(k , n - 1 - i);
	    		sum_bit += ai_Array[i];
	    	}

	    	System.out.println((int)sum_all%sum_bit );
	    	}

	    }