#include <bits/stdc++.h>
using namespace std;
int n, p, q, a[2002], dp[2002][2002], next1[2002], next2[2002];
int main()
{
cin >> n >> p >> q;
for (int i = 1; i <= n; i++)
cin >> a[i];
sort(a + 1, a + n + 1);
if (p + q >= n) {
cout << 1;
return 0;
}
int st = 1, dr = 1e9, ans = 0;
while (st <= dr) {
int mij = (st + dr) / 2;
for (int i = 1; i <= n; i++) {
next1[i] = lower_bound(a + 1, a + n + 1, a[i] + mij) - a - 1;
next2[i] = lower_bound(a + 1, a + n + 1, a[i] + 2 * mij) - a - 1;
}
next1[n + 1] = next2[n + 1] = n;
for (int i = 0; i <= p; i++)
for (int j = 0; j <= q; j++) {
if (!i && !j)
continue;
dp[i][j] = 0;
if (i)
dp[i][j] = next1[dp[i - 1][j] + 1];
if (j)
dp[i][j] = max(dp[i][j], next2[dp[i][j - 1] + 1]);
}
if (dp[p][q] < n) {
st = mij + 1;
}
else {
ans = mij;
dr = mij - 1;
}
}
cout << ans;
return 0;
}
