#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
#define pf push_front
#define mp make_pair
#define ll long long
int n, p, q;
bool dpcheck(int w, vector<int> sections) {
vector<vector<int>> dp(p + 1, vector<int>(q + 1));
dp[0][0] = 0;
for (int i=1;i<p+1;i++) {
if (dp[i - 1][0] == n) {
dp[i][0] = n;
continue;
}
dp[i][0] = upper_bound(sections.begin(), sections.end(), sections[dp[i - 1][0]] + w - 1) - sections.begin();
}
for (int i=1;i<q+1;i++) {
if (dp[0][i - 1] == n) {
dp[0][i] = n;
continue;
}
dp[0][i] = upper_bound(sections.begin(), sections.end(), sections[dp[0][i - 1]] + 2*w - 1) - sections.begin();
}
for (int i=1;i<p+1;i++) {
for (int j=1;j<q+1;j++) {
if (dp[i][j - 1] == n || dp[i - 1][j] == n) {
dp[i][j] = n;
continue;
}
dp[i][j] = upper_bound(sections.begin(), sections.end(), sections[dp[i][j - 1]] + 2*w - 1) - sections.begin();
dp[i][j] = max(dp[i][j], (int)(upper_bound(sections.begin(), sections.end(), sections[dp[i - 1][j]] + w - 1) - sections.begin()));
}
}
return (dp[p][q] == n);
}
int main() {
cin >> n >> p >> q;
vector<int> sections(n);
for (int i=0;i<n;i++) {
cin >> sections[i];
}
sort(sections.begin(), sections.end());
if (p + q >= n) {
cout << 1;
} else {
int top = 1000000000, bottom = 0, mid;
while (top > bottom + 1) {
mid = (top + bottom) / 2;
if (dpcheck(mid, sections)) {top = mid;}
else {bottom = mid;}
}
cout << top;
}
}
