#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define N 2001
int n, p, q, dp[N][N];
ll a[N];
int binsearch(int l, int r, ll x) {
int i = (l+r)/2;
while (l != i && i != r) {
if (a[i] <= x)
l = i;
else
r = i;
i = (l+r)/2;
}
for (int i = l; i <= r; i++)
if (a[i] > x)
return i;
return n+1;
}
bool check(int w) {
for (int i = 0; i <= p; i++)
for (int j = 0; j <= q; j++)
dp[i][j] = 0;
dp[0][1] = binsearch(1, n, a[1]+2*w-1)-1;
dp[1][0] = binsearch(1, n, a[1]+w-1)-1;
for (int i = 1; i <= p; i++)
for (int j = 1; j <= q; j++) {
int tmp1 = binsearch(1, n, a[dp[i-1][j]+1]+1ll*w-1) - 1;
int tmp2 = binsearch(1, n, a[dp[i][j-1]+1]+1ll*2*w-1) - 1;
dp[i][j] = max(dp[i-1][j], max(dp[i][j-1], max(tmp1, tmp2)));
if (dp[i][j] == n)
return true;
}
return false;
}
signed main() {
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
cin >> n >> p >> q;
for (int i = 1; i <= n; i++)
cin >> a[i];
if (p+q >= n) {
cout << 1 << '\n';
return 0;
}
sort(a+1, a+1+n);
int l = 1, r = 1000000000, ans = 0;
while (l <= r) {
int mid = (l+r)/2;
if (check(mid)) {
ans = mid;
r = mid-1;
}
else l = mid+1;
}
cout << ans << '\n';
return 0;
}
