#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
int N, P, Q;
cin >> N >> P >> Q;
vector<int> A(N);
for(int i = 0; i < N; ++i) cin >> A[i];
sort(A.begin(), A.end());
if(P + Q >= N) {
cout << 1 << endl;
return 0;
}
int L = 0, R = (1 << 30) - 17;
while(R - L > 1) {
int M = (L + R) >> 1;
vector<int> watchp(N + 1), watchq(N + 1);
for(int i = 0; i <= N; ++i) {
watchp[i] = (i >= 1 ? watchp[i - 1] : 0);
watchq[i] = (i >= 1 ? watchq[i - 1] : 0);
while(watchp[i] != N && A[watchp[i]] - A[i] < M) ++watchp[i];
while(watchq[i] != N && A[watchq[i]] - A[i] < 2 * M) ++watchq[i];
}
vector<vector<int> > dp(P + 1, vector<int>(Q + 1, 0));
for(int i = 0; i <= P; ++i) {
for(int j = 0; j <= Q; ++j) {
if(i >= 1) dp[i][j] = max(dp[i][j], watchp[dp[i - 1][j]]);
if(j >= 1) dp[i][j] = max(dp[i][j], watchq[dp[i][j - 1]]);
}
}
if(dp[P][Q] == N) R = M;
else L = M;
}
cout << R << endl;
return 0;
}
