you are given an array of size N. You need to select K elements from the array such that the difference between the max number among selected and the min number among selected array elements should be minimum. Print the minimum difference.

INPUT:
First line N number i.e., length of array
Second line K number 
Next N lines contains a number for each line

OUTPUT:
Print the minimum possible difference

0<N<10^5
0<K<N
0<number<10^9

SAMPLE INPUT
5
3
1
2
3
4
5

SAMPLE OUTPUT
2
import sys
n=input()
k=input()
l=[]
n1=n
while n1>0:
    l.append(input())
    n1-=1
l.sort()
mn=9999999999999999
for i in xrange(k-1,n):
    if l[i]-l[i-k+1]<mn:
        mn=l[i]-l[i-k+1]
print mn