#include <bits/stdc++.h>
#define in cin
using namespace std;
int n ,p ,q;
vector<int> a;
int nx[2005],nxd[2005];
int dp[2005][2005]; // nr minim de tip 2 pentru maxim i de tip 1
int check(int w){
//cout << "START OF TEST :" << w << '\n';
for(int i = 1; i <= n; i++){
nx[i] = upper_bound(a.begin(),a.end(),a[i]+w-1)-a.begin();
}
for(int i = 1; i <= n; i++){
nxd[i] = upper_bound(a.begin(),a.end(),a[i]+2*w-1)-a.begin();
//cout << a[i]+2*w << ' ' << nxd[i];
//cout<< '\n';
}
//cout << "END OF TEST\n";
//
for(int i = n ; i > 0 ;i--)
for(int k = 0 ; k <= p ; k++)
dp[i][k] = 0;
//
for(int i = n ; i > 0 ;i--){
for(int k = 0 ; k <= p ; k++){
dp[i][k] = dp[nxd[i]][k] + 1;
if(k > 0)
dp[i][k] = min(dp[nx[i]][k-1],dp[i][k]);
}
}
//
if(dp[1][p] <= q)return 1;
else return 0;
}
ifstream fin("in1.i");
int32_t main(){
ios_base :: sync_with_stdio(0); cin.tie(); cout.tie();
in >> n >> p >> q;
int nt;
a.push_back(0);
for(int i = 1; i <= n; i++){
in >> nt;
a.push_back(nt);
}
if(p + q >= n){
cout << 1;
return 0;
}
sort(a.begin(),a.end());
int l = 1 , r = 1e9;
while(l < r){
int mid = (l+r)/2;
if(check(mid)){
r = mid;
}else{
l = mid+1;
}
}
cout << l;
}
