#include <bits/stdc++.h>
using namespace std;
#define MAX_N 2000
#define inf 1e9
int nbEvents, nbSmall, nbLarge;
vector<int> eventTime;
vector<int> target_w;
vector<int> target_2w;
int dp[MAX_N][MAX_N];
int get_dp (int node, int picture) {
if (picture == -1) return inf;
if (node == -1) return 0;
return dp[node][picture];
}
bool test_w (int w) {
int l = -1;
for (int r = 0; r < nbEvents; r ++) {
while (eventTime[l + 1] + w <= eventTime[r])
l ++;
target_w[r] = l;
}
l = -1;
for (int r = 0; r < nbEvents; r ++) {
while (eventTime[l + 1] + 2 * w <= eventTime[r])
l ++;
target_2w[r] = l;
}
for (int i = 0; i < nbEvents; i ++) {
for (int j = 0; j <= nbLarge; j ++) {
dp[i][j] = min(
get_dp(target_w[i], j) + 1,
get_dp(target_2w[i], j - 1)
);
}
}
int min_p = inf;
for (int j = 0; j <= nbLarge; j ++)
min_p = min(min_p, dp[nbEvents - 1][j]);
return min_p <= nbSmall;
}
int compute_w () {
if (nbSmall + nbLarge >= nbEvents) return 1;
int a = 0;
int b = inf;
while (b - a > 1) {
int wc = (a + b) >> 1;
if (test_w(wc)) b = wc;
else a = wc;
}
return b;
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> nbEvents >> nbSmall >> nbLarge;
eventTime.resize(nbEvents);
target_w .resize(nbEvents);
target_2w.resize(nbEvents);
for (int iE = 0; iE < nbEvents; iE ++)
cin >> eventTime[iE];
sort(eventTime.begin(), eventTime.end());
cout << compute_w();
}
