#include <bits/stdc++.h>
int n, k, q, a[2005];
int ls[2005], st[2005], con;
int work(int mini) {
  int last = -1;
  con = 0;
  for (int i = 1; i <= n; i++) ls[i] = a[i];
  for (int i = 1; i <= n + 1; i++) {
    if (a[i] >= mini && last == -1) last = i;
    if (a[i] < mini && ~last) {
      std::sort(ls + last, ls + i);
      for (int j = last; j <= i - k; j++) st[con++] = ls[j];
      last = -1;
    }
  }
  if (con < q) return 0x3f3f3f3f;
  std::sort(st, st + con);
  return st[q - 1] - mini;
}
int main() {
  scanf("%d%d%d", &n, &k, &q);
  a[n + 1] = -1;
  int ans = 0x3f3f3f3f;
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  for (int i = 1; i <= n; i++) ans = std::min(ans, work(a[i]));
  printf("%d\n", ans);
}
