#include <bits/stdc++.h>
using namespace std;
int n, k, q, a[20005], b[20005], c[20005], tmp[20005], tot, ans;
void clr(int l, int r) {
  int i;
  int len = (r - l + 1);
  for (i = l; i <= r; ++i) tmp[i] = a[i];
  sort(tmp + l, tmp + r + 1);
  while (len >= k) {
    c[++tot] = tmp[l];
    ++l, --len;
  }
}
void work(int x) {
  tot = 0;
  int i;
  for (i = 1; i <= 2000; ++i) c[i] = 2e9 + 7;
  int l = 1, r = 1;
  while (l <= n) {
    while (a[r] >= x && r <= n) ++r;
    --r;
    if (r < l) {
      ++l, r = l;
      continue;
    }
    clr(l, r);
    l = r + 1;
    ++r;
  }
  sort(c + 1, c + tot + 1);
  ans = min(ans, c[q] - x);
}
int main() {
  int i;
  ans = 1e9 + 7;
  scanf("%d%d%d", &n, &k, &q);
  for (i = 1; i <= n; ++i) {
    scanf("%d", &a[i]);
    b[i] = a[i];
  }
  sort(b + 1, b + n + 1);
  for (i = 1; i <= n; ++i) work(b[i]);
  printf("%d", ans);
  return 0;
}
