#include <bits/stdc++.h>
using namespace std;
int tab[2010];
int dp[2010][2010];
int n, p, q;
bool check(int x) {
int pop1 = 1;
int pop2 = 1;
for(int i = 1; i <= n; i++) {
while(tab[i] - tab[pop1] + 1 > x) {
pop1++;
}
while(tab[i] - tab[pop2] + 1 > 2 * x) {
pop2++;
}
dp[i][0] = dp[pop2 - 1][0] + 1;
for(int j = 1; j <= p; j++) {
dp[i][j] = min(dp[pop1 - 1][j - 1], dp[pop2 - 1][j] + 1);
}
}
int ans = 1e9;
for(int j = 0; j <= p; j++) {
ans = min(ans, dp[n][j]);
}
return ans <= q;
}
int main() {
//ios_base::sync_with_stdio(0);
//cin.tie(0);
cin >> n >> p >> q;
for(int i = 1; i <= n; i++) {
cin >> tab[i];
}
sort(tab + 1, tab + n + 1);
if(p >= n || q >= n) {
cout << 1 << '\n';
return 0;
}
int l = 1;
int r = 1e9;
while(l < r) {
int mid = (l + r) / 2;
if(check(mid)) {
r = mid;
}
else {
l = mid + 1;
}
}
cout << l << '\n';
}
