import java.util.Arrays;
import java.util.Scanner;


public class Main {
	public static void main(String[] a) {
		Scanner s=new Scanner(System.in);
		int[] A=new int[s.nextInt()];s.nextInt();
		int i=0;
		while(s.hasNext())A[i++]=s.nextInt();
		Arrays.sort(A);
		System.out.println(A[i-1]-A[0]);
	}
}