#include <bits/stdc++.h>
using namespace std;
#define ll long long
bool check(int n, int p, int q, vector<ll> &a, int w) {
vector<ll> x (n+1, n), y (n+1, n);
int b = 0, e = 0;
while (b < n) {
if (a[e]-a[b]+1 <= w) {
e++;
}
else {
x[b] = e;
b++;
}
}
b = 0, e = 0;
while (b < n) {
if (a[e]-a[b]+1 <= 2*w) {
e++;
}
else {
y[b] = e;
b++;
}
}
vector<vector<int>> dp (p+1, vector<int> (q+1, -1));
dp[0][0] = 0;
for (int i = 1; i <= p; i++) {
dp[i][0] = x[dp[i-1][0]];
}
for (int i = 1; i <= q; i++) {
dp[0][i] = y[dp[0][i-1]];
}
for (int i = 1; i <= p; i++) {
for (int j = 1; j <= q; j++) {
dp[i][j] = max(x[dp[i-1][j]], y[dp[i][j-1]]);
}
}
return (dp[p][q] == n);
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, p, q;
cin >> n >> p >> q;
vector<ll> a (n, 0);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
sort(a.begin(), a.end());
a.push_back(1e12);
if (p+q >= n) {
cout << 1 << '\n';
return 0;
}
int pow = 1<<30;
int w = 0;
while (pow > 0) {
w += pow;
if (check(n, p, q, a, w)) {
w -= pow;
}
pow /= 2;
}
cout << w+1 << '\n';
}
