#include <bits/stdc++.h>

#define For(i, j, k) for (int i = j; i <= k; i++)

using namespace std;

const int N = 2010;

int A[N], rk[N];
int n, k, q;

bool cmp(int x, int y) {
	return A[x] < A[y];
}

int bel[N], cnt[N];

int main() { 

	scanf("%d%d%d", &n, &k, &q);
	For(i, 1, n) scanf("%d", &A[i]), rk[i] = i;
	sort(rk + 1, rk + n + 1, cmp);

	int ans = 1e9;
	For(i, 1, n - q + 1) {
		For(j, 0, n) cnt[j] = 0;
		For(j, 0, n) {
			bel[j] = A[j] < A[rk[i]] ? j : bel[j - 1];
			if (bel[j] != j) ++cnt[bel[j]];
		}
		int ret = 0;
		For(j, i, n) 
			if (cnt[bel[rk[j]]] >= k) {
				++ret, --cnt[bel[rk[j]]];
				if (ret >= q) {
					ans = min(ans, A[rk[j]] - A[rk[i]]);
					break;
				}
			}
	}
	printf("%d\n", ans);

	return 0;
}