#include <bits/stdc++.h>
#define int long long
#define N 2050
#define f first
#define s second
using namespace std;
typedef pair<int, int> pii;
int n, p, q, v[N];
int prox(int i, int w)
{
int ini = i, fim = n, mid, best;
while(fim >= ini)
{
mid = (ini + fim)/2;
if(v[mid] - v[i] + 1 <= w) best = mid, ini = mid + 1;
else fim = mid - 1;
}
return best + 1;
}
struct ss
{
int a, b, c;
ss(int ai, int bi, int ci){ a = ai, b = bi, c = ci;}
bool operator < (const ss &t) const
{
if(a != t.a) return a < t.a;
if(b != t.b) return b < t.b;
return c < t.c;
}
};
map< ss, bool > mapa;
bool solve(int i, int p, int q, int w)
{
if(i > n) return true;
if(mapa.find({i, p, q}) != mapa.end()) return mapa[{i, p, q}];
bool small = p ? solve(prox(i, w), p - 1, q, w) : 0;
bool big = q ? solve(prox(i, 2*w), p, q - 1, w) : 0;
return mapa[{i, p, q}] = small || big;
}
int32_t main()
{
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>p>>q;
for(int i = 1; i <= n; i++) cin>>v[i];
if(p + q >= n)
{
cout<<"1\n";
return 0;
}
sort(v + 1, v + n + 1);
int ini = 0, fim = 1e9, mid, best = -1;
while(fim >= ini)
{
mapa.clear();
mid = (ini + fim)/2;
if(solve(1, p, q, mid)) best = mid, fim = mid - 1;
else ini = mid + 1;
}
cout<<best<<"\n";
}
