#include<bits/stdc++.h>
using namespace std;
bool M1;
#define PI 3.14159265358979323846
#define sz(a) (int)a.size()
#define all(x) x.begin(),x.end()
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii,ii>
#define se second
#define fi first
#define ffi fi.fi
#define sfi se.fi
#define sse se.se
#define fse fi.se
#define lt(i, c, d) for(int i = c; i <= d; ++i)
#define fl(i, c, d) for(int i = d; i >= c; --i)
#define pb push_back
#define emb emplace_back
#define emf emplace_front
#define em emplace
#define look_memory cerr<<abs(&M2-&M1)/1024.0/1024<<'\n'
#define look_time cerr << "TIME : " << clock() * 0.001 << "s" <<'\n'
const int N=2e3+5,lg=30,mod=998244353;
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int Rand(int u,int v){
return u+rd()%(v-u+1);
}
int dx[]={1,0,-1,0,1,1,-1,-1};
int dy[]={0,-1,0,1,1,-1,1,-1};
int node,a[N],p,q;
int dp[N],dpcur[N];
bool check(int mid){
memset(dp,0,sizeof dp);
memset(dpcur,0,sizeof dpcur);
for(int i=1,j=1;i<=node;++i){
while(a[i]-a[j]+1>mid)++j;
dp[i]=dp[j-1]+1;
}
if(dp[node]<=p)return true;
for(int _=1;_<=q;++_){
int jp=1,jq=1;
for(int i=1;i<=node;++i){
while(a[i]-a[jp]+1>mid)++jp;
while(a[i]-a[jq]+1>mid*2)++jq;
dpcur[i]=dp[jq-1];
dpcur[i]=min(dpcur[i],dpcur[jp-1]+1);
}
// for(int i=1;i<=node;++i)cout <<dpcur[i]<<" ";cout<<'\n';
if(dpcur[node]<=p)return true;
for(int i=1;i<=node;++i)dp[i]=dpcur[i];
}
return false;
}
bool M2;
void solve(){
cin >> node >> p >> q;
if(p+q>=node){
cout <<1;
}
for(int i=1;i<=node;++i){
cin >> a[i];
}
sort(a+1,a+1+node);
int l=1,r=1e9,res=1;
while(l<=r){
int mid=(r+l)>>1;
if(check(mid)){
r=mid-1;
res=mid;
}
else l=mid+1;
}
cout << res;
}
main()
{
srand(time(0));
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
#define task "paleta"
if(fopen(task".inp","r")){
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
int t=1;
solve();cout<<'\n';
look_memory;
look_time;
}
