import java.io.*;
import java.util.*;
public class Main{
    public static void main(String[] args) {
        var sc = new Scanner(System.in);
        var ou = new PrintWriter(System.out);
        int n = Integer.parseInt(sc.next());
        int k = Integer.parseInt(sc.next());
        long x = 0;
        long y = 0;
        for(int i = 0 ; i < n ; i++){
            int a = Integer.parseInt(sc.next());
            x *= k;
            x += a;
            y += a;
        }
        ou.println(x % y);
        sc.close();
        ou.flush();
    }
}