#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define pb push_back
#define vll vector<ll>
#define pll pair<ll, ll>
typedef long long ll;
const ll mxN=2005;
const ll inf=1e17;
ll n, p, q;
ll a[mxN];
ll dp[mxN][mxN];
ll o[mxN];
ll s[mxN];
bool check(ll tar){
for(ll i=0;i<=n;i++){
for(ll j=0;j<=p;j++){
dp[i][j]=inf;
}
}
for(ll i=0;i<=p;i++){
dp[0][i]=0;
}
ll pt=0;
for(ll i=0;i<n;i++){
while(pt<n && a[pt]-a[i]+1<=tar){
pt++;
}
o[i]=pt;
}
//cout<<"dumb "<<o[8]<<'\n';
pt=0;
for(ll i=0;i<n;i++){
while(pt<n && a[pt]-a[i]+1<=2*tar){
pt++;
}
s[i]=pt;
}
for(ll i=0;i<n;i++){
for(ll j=0;j<=p;j++){
//cout<<i<<' '<<j<<' '<<dp[i][j]<<'\n';
// take small
dp[o[i]][j]=min(dp[o[i]][j], dp[i][j]+1);
//take big
dp[s[i]][j+1]=min(dp[s[i]][j+1], dp[i][j]);
}
}
//cout<<"checking "<<tar<<' '<<dp[n][p]<<'\n';
//cout<<q<<' '<<(dp[n][p]<=q)<<'\n';
return (dp[n][p]<=q);
}
void solve(){
cin>>n>>q>>p;
for(ll i=0;i<n;i++){
cin>>a[i];
}
sort(a, a+n);
/*for(ll i=0;i<n;i++){
cout<<a[i]<<' ';
}
cout<<'\n';*/
if(p+q>=n){
cout<<1<<'\n';
return;
}
ll ans;
ll l=1, r=1e9+5;
while(l<=r){
ll mid=(l+r)/2;
if(check(mid)){
//cout<<mid<<" good\n";
ans=mid;
r=mid-1;
}
else{
//cout<<mid<<" bad\n";
l=mid+1;
}
}
cout<<ans<<'\n';
//check(8);
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
solve();
return 0;
}
