package ST;

import java.util.Scanner;

/**

* @auther: WJoe

* @Description:

* @Date : 19:33 2018/9/7

*/

public class Main1 {

public static void main(String[] args) {

Scanner scanner = new Scanner(System.in);

int n = scanner.nextInt();

int k = scanner.nextInt();

long[] ints = new long[n];

long sum = 0;

for (int i = 0; i < n; i++) {

ints[i] = scanner.nextLong();

sum += ints[i];

}

if (n == 0) {

System.out.println(0);

return;

}

double avg = (double)sum / n;

long max = Integer.MIN_VALUE;

long min = Integer.MAX_VALUE;

for (int i = 0; i < n; i++) {

if (ints[i] > avg) {

ints[i] = ints[i] - k;

} else ints[i] = ints[i] + k;

max = Math.max(max, ints[i]);

min = Math.min(min, ints[i]);

}

System.out.println(max - min);

}

}