#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
int a[2020];
int t[2020],tt[2020],nt;
int aa[2020],an;
bool ch[2020],in[2020];
bool cmp(int x,int y)
{
	return a[x]<a[y];
}
int main()
{
	int n,k,q;
	int ans=2147483647;
	scanf("%d%d%d",&n,&k,&q);
	for(int i=1;i<=n;i++)
		scanf("%d",&a[i]);
	memset(in,0,sizeof(in));
	for(int i=1;i<=n;i++)
		t[i]=i;
	sort(t+1,t+1+n,cmp);
	an=0;
	for(int i=n;i>=1;i--)
	{
		ch[t[i]]=true;
		nt=0;
		an=0;
		for(int j=1;j<=n+1;j++)
		{
			if(ch[j])
				tt[++nt]=j;
			else
			{
				sort(tt+1,tt+1+nt,cmp);
				for(int kk=1;kk<=nt-k+1;kk++)
					aa[++an]=a[tt[kk]];
				nt=0;
			}
		}
		sort(aa+1,aa+an+1);
		if(an>=q)
			ans=min(ans,aa[q]-aa[1]);
	}
	printf("%d\n",ans);
	return 0;
}