#include <bits/stdc++.h>
using namespace std;
int n, k, q;
int a[2005];
int p;
int t[2005];
int b[2005];
int c[2005];
int pp, ppp;
int s;
int ans;
int sum;
int r;
int main() {
  cin >> n >> k >> q;
  ans = 0x3f3f3f3f;
  for (int i = 1; i <= n; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) {
    p = 0, s = 0, sum = 0;
    pp = 0;
    ppp = 0;
    for (int j = 1; j <= n; j++)
      if (a[j] >= a[i]) t[++p] = j;
    if (p < q) continue;
    for (int j = 1; j <= p; j++) cout << t[j] << " ";
    cout << endl;
    for (int j = 1; j <= p + 1; j++) {
      if (t[j] == t[j - 1] + 1) {
        s++;
      } else {
        pp = 0;
        if (s >= k) {
          for (int l = j - s; l < j; l++) b[++pp] = a[t[l]];
          sort(b + 1, b + pp + 1);
          for (int l = 1; l <= s - k + 1; l++) c[++ppp] = b[l];
        }
        s = 1;
      }
    }
    if (ppp >= q) ans = min(ans, c[q] - a[i]);
  }
  cout << ans;
}
