package yukicoder;

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

public class Yuki21 {
	
	public static void main(String[] args) {		
		Scanner scan = new Scanner(System.in);
		int count = scan.nextInt();
		int group = scan.nextInt();
		int[] numArr = new int[count];
		for (int i = 0; i < count; i++ ) {
			numArr[i] = scan.nextInt();
		}
		scan.close();
		Arrays.sort(numArr);
		System.out.println(numArr[count-1] - numArr[0]);
	}
}