#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <utility>
#include <algorithm>
#include <cstring>
int x, p, q;
std::vector<int> arr;
int dp[2001][2001];
int next[2][2001];
int solve(int pos, int k) {
if (k>q) {
return 0x3f3f3f3f;
}
if (pos==x) {
return 0;
}
if (dp[pos][k]!=-1) {
return dp[pos][k];
}
int ret = solve(next[1][pos],k+1);
for (int i = pos; i < next[0][pos]; i++) {
ret = std::min(ret, 1 + solve(i+1,k));
}
return dp[pos][k] = ret;
}
bool can_solve(int cap) {
for (int i = 0; i < 2; i++) {
for (int l = x-1, r = x-1; l >= 0; l--) {
while (arr[r]-arr[l]+1>(i+1)*cap) {
--r;
}
next[i][l] = r+1;
}
}
memset(dp,-1,sizeof(dp));
return solve(0,0) <= p;
}
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(NULL);
std::cout.tie(NULL);
std::cin >> x >> p >> q;
// we only need at most x cameras in total, out of which we'll greedily take as many big cameras as possible
if (p+q>x) {
q = std::min(q, x);
p = x-q;
}
for (int i = 0, tmp; i < x; i++) {
std::cin >> tmp;
arr.emplace_back(tmp);
}
std::sort(arr.begin(),arr.end());
const auto bs = [&]() {
int ret = 1000000001;
int l = 1, r = 1000000000;
while (l<=r) {
int m = (l+r)>>1;
if (can_solve(m)) {
ret = m;
r = m-1;
}
else {
l = m+1;
}
}
return ret;
};
std::cout << bs() << "\n";
//can_solve(bs(),1);
}
