#include <bits/stdc++.h>
#define mod 1000000007
#define pb push_back
#define mid(l, r) ((l)+(r))/2
#define len(a) (a).length()
#define sz(a) (a).size()
#define xx first
#define yy second
#define inf int(2e9)
#define ff(i, a, b) for(int (i) = (a); (i) <= (b); ++(i))
#define fb(i, a, b) for(int (i) = (a); (i) >= (b); --(i))
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
template<class T>
void print(const T niz[], const int siz)
{
for(int i=0;i<siz;i++)
cout << niz[i] << " ";
cout << endl;
}
int n,p,q;
int dp[2004][2004];
int niz[2005];
bool moze(int w){
for(int i=0; i<=2000; i++)dp[0][i] = 0;
int cnmale = 0;
int cnvel = 0;
for(int i=1; i<=n; i++){
while(niz[cnmale] <= niz[i] - w)cnmale++;
if(cnmale != 0)cnmale--;
while(niz[cnvel] <= niz[i] - 2*w)cnvel++;
if(cnvel != 0)cnvel--;
for(int j=0; j<=q; j++){
int tr = 1e9;
tr = dp[cnmale][j] + 1;
if(j != 0)tr = min(tr, dp[cnvel][j - 1]);
dp[i][j] = tr;
}
}
if(dp[n][q] <= p)return 1;
return 0;
}
int main()
{
ios_base::sync_with_stdio(false);
cin >> n >> p >> q;
p = min(p,n);
q = min(q,n);
for(int i=1; i<=n; i++){
cin >> niz[i];
}
sort(niz + 1, niz + n + 1);
int l = 1;
int r = 1e9;
while(l < r){
int mid = (l + r) / 2;
if(moze(mid))r = mid;
else l = mid + 1;
}
cout << l << endl;
return 0;
}
