#include <bits/stdc++.h>
#define DIM 2010
#define INF 1000000000
using namespace std;
int v[DIM],dp[DIM][DIM];
int n,p,q,i;
int get_poz (int x){
int st = 1, dr = n, sol = 0;
while (st <= dr){
int mid = (st+dr)>>1;
if (v[mid] >= x){
sol = mid;
dr = mid-1;
} else st = mid+1;
}
return sol;
}
int verif (int val){
for (int i=1;i<=n;i++)
for (int j=0;j<=n;j++)
dp[i][j] = INF;
for (int i=1;i<=n;i++){
int poz = get_poz (v[i] - val + 1);
int poz2 = get_poz (v[i] - 2 * val + 1);
for (int j=1;j<=p;j++)
dp[i][j] = min (dp[poz-1][j-1], dp[poz2-1][j] + 1);
}
if (dp[n][p] <= q)
return 1;
return 0;
}
int main (){
//ifstream cin ("date.in");
//ofstream cout ("date.out");
cin>>n>>p>>q;
for (i=1;i<=n;i++)
cin>>v[i];
sort (v+1,v+n+1);
p = min (p,n), q = min (q,n);
int st = 0, dr = INF, sol = 0;
while (st <= dr){
int mid = (st+dr)>>1;
if (verif(mid)){
sol = mid;
dr = mid-1;
} else st = mid+1;
}
cout<<sol;
return 0;
}
