#include <bits/stdc++.h>

using namespace std;

typedef long long int64;

int N, M, K, A[100000];

bool check(int idx)
{
  multiset< int > vv;
  for(int i = 0; i < N; i++) {
    if(i != idx) vv.emplace(A[i]);
  }
  int64 beet = A[idx] + K;
  multiset< int >::iterator it = vv.begin();
  int ret = 0;

  while(it != vv.end()) {
    auto st = vv.upper_bound(beet - A[*it]);
    if(it == st) ++st;
    if(st != vv.end()) vv.erase(st), ++ret;
    it = vv.erase(it);
  }
  return (ret < M);
}

int main()
{

  cin >> N >> M;
  --N;
  cin >> K;
  for(int i = 0; i < N; i++) cin >> A[i];

  if(!check(A[N - 1])) {
    cout << -1 << endl;
    return (0);
  }

  int low = 0, high = N - 1;
  while(high - low > 0) {
    int mid = (low + high) / 2;
    if(check(mid)) high = mid;
    else low = mid + 1;
  }
  cout << A[low] << endl;
}