#include<cstdio>
#include<vector>
#include<algorithm>


using namespace std;


int n, m, k;
vector<int> a;


void min_u(int& d, int v)
{
	if(d>v) d=v;
}


int solve(void)
{
	int partner=-1, score, min_score, chk_score;
	int i, s, e;

	for(i=0;i<a.size();i++)
	{
		score=k+a[i];
		s=0;
		e=2*m;
		if(i>=2*m) e--;

		min_score=2000000001;
		for(;s<e;s++,e--)
		{
			if(s==i) s++;
			if(e==i) e--;
			chk_score=a[s]+a[e];
			min_u(min_score, chk_score);
		}

		if(min_score<=score)
		{
			partner=a[i];
		}
		else
		{
			break;
		}
	}
	return partner;
}


int main(void)
{

	while(scanf("%d%d", &n, &m)==2)
	{
		scanf("%d", &k);
		a.resize(n-1);
		for(int i=0;i<n-1;i++)
		{
			scanf("%d", &a[i]);
		}
		sort(a.begin(), a.end(), greater<int>());

		printf("%d\n", solve());
	}

	return 0;
}