#include <algorithm>
using namespace std;
int a[101000];
int n,m,mx,mn;
int main(){
	cin>>n>>m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	int sb1=1,sb2=n;
	sort(a+1,a+n+1);
	mn=a[sb1];
	mx=a[sb2];
	int s=1e9;
			while(sb1<=sb2&&mn<=mx&&m){
		if(a[sb2-1]-mn<=mx-a[sb1+1])
			mx=a[sb2-1],s=min(s,a[sb2-1]-a[sb1]),sb2--;
		else mn=a[sb1+1],s=min(s,a[sb2]-a[sb1+1]),sb1--;
		m--;
	}
	cout<<s;

}