#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstdlib>
using namespace std;
int eventsNo, smallNo, largeNo;
vector<int> events;
vector< vector<int> > dp;
bool works(int width)
{
dp.assign(smallNo + 1, vector<int>(largeNo + 1, -1));
for (int pq = 1; pq <= largeNo + smallNo; ++pq) {
for (int p = 0; p <= smallNo; ++p) {
int q = pq - p;
if (q < 0 || q > largeNo) continue;
if (p > 0) {
int firstIdx = dp[p-1][q] + 1;
int firstEvent = events[firstIdx];
int lastIdx = firstIdx;
while (lastIdx + 1 < eventsNo && (events[lastIdx + 1] <= firstEvent + width - 1)) ++lastIdx;
dp[p][q] = min(lastIdx, eventsNo - 1);
// cerr << width << ", dp[" << p << "][" << q << "]: " << firstIdx << " " << lastIdx << endl;
//
}
if (q > 0) {
int firstIdx = dp[p][q-1] + 1;
int firstEvent = events[firstIdx];
int lastIdx = firstIdx;
while (lastIdx + 1< eventsNo && events[lastIdx + 1] <= firstEvent + 2*width - 1) ++lastIdx;
dp[p][q] = max(dp[p][q], min(lastIdx, eventsNo - 1));
}
// cerr << width << ", dp[" << p << "][" << q << "]: " << dp[p][q] << endl;
}
}
return dp[smallNo][largeNo] == eventsNo - 1;
}
int binarySearch()
{
int left = 0, right = 1e9 + 7;
while (true) {
// cerr << left << ' ' << right << endl;
if (right - left <= 3) {
while (!works(left)) ++left;
return left;
}
int mid = left + (right - left) / 2;
if (works(mid)) right = mid;
else left = mid + 1;
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie();
cin >> eventsNo >> smallNo >> largeNo;
events.assign(eventsNo, 0);
for (int i = 0; i < eventsNo; ++i) {
cin >> events[i];
}
sort(events.begin(), events.end());
if (smallNo + largeNo >= eventsNo) {
cout << 1 << endl;
return 0;
}
// cout << works(4) << endl;
cout << binarySearch() << endl;
}
